This is a tentative rework for Zilean, the Chronokeeper. While an iconic character in the League roster, the Zilsta's been in fairly sad shape for years: with most of his power locked away into power that's either too personal for a champion who should be projecting his power as much onto allies and enemies as possible (i.e. Rewind), or not nearly appreciable enough at any point in the game (Heightened Learning), Zil's been stuck in a position where he doesn't really have enough offensive power or damage to be a decent mage, nor does he have enough overall utility to compete as a support. More importantly, though, it's practically impossible to give him more utility or damage on his current kit, again because of its wonky structure. Until recently, too, Zilean was fairly unhealthy to deal with due to his massively damaging and reliable early poke, though that became much less of an issue when he got a mini-rework in V5.4. Following those changes, Zilean ended up being a lot more healthy, but still kept most of his core issues, and so didn't really pick up in popularity or player-side enjoyment. More deeply, though, Zilean feels like a huge missed opportunity, as he could have access to some pretty crazy effects as a time mage, yet has a kit that, bar some pretty cool mechanics, doesn't really convey a time theme in the most interesting manner.
To answer this, I think the most important change that needs to happen is for Zilean to have access to more direct power, and his abilities should be shuffled around to give him access to a powerful array of time-bending abilities, one that would work well both on a mage and a support. With the advent of newer champions with funkier, often double-edged abilities, Zilean could also benefit from tremendously powerful, unique and versatile utility, which could allow him to not only allow him to alter time in pretty much every aspect, but also assert himself as a powerful area control champion, capable of altering the flow of combat and using his abilities on many different members of either team at any given time. At the core of this new kit would be the ability to enhance them via "smart" double-tapping, as is already the case with the spruced-up Time Bomb: double-casting any of Zilean's basic abilities should be a unique decision point of its own (e.g. "Do I want more damage, more CC or more utility?"), but double-casting them in a truly skillful manner should also unlock totally new and massively strong instances of power.
COOLDOWN:20 / 15 / 10
Innate:Zilean can cast basic abilities while they are on cooldown, placing the recast ability and Borrowed Time on cooldown.
Additionally, Zilean's abilities and their duplicates gain additional effects when they touch each other, though targets can only be affected by their basic effects once per double-cast.
As with all global passives, Heightened Learning had to be severely toned down for each champion so as to not be overpowered, and is one of the ways I feel Zilean's power is locked out. It's a passive that doesn't do that much, and only gives a subtle (yet powerful) power increase to his team without giving a substantial feeling of strength. It's also not particularly relevant to his theme (i.e. time), at least not in a manner that is especially interesting, even if toying with experience is a rare feature.
Essentially, Borrowed Time is Rewind implemented as a passive. That way, it gives Zilean more visible power from the get-go, and frees up an ability slot for something more interesting (and that can be used at level 1). It also offers a lot more options as a support, as he now actively has to choose which ability to use while on cooldown (double bombs, double slow, etc.), along with the bonus effect he wants to attain.
Along with that, I nerfed Zilean's movement speed to 325 from 335 and made it more difficult for him to boost his own movement through his abilities. The idea here is that Zilean would have a ton of ways of controlling and denying areas, and thus creating safety for himself, and so he should be fairly vulnerable if attacked directly through all of his massive AoE. I made a few other significant base stat changes to contribute to his vulnerability, reducing his base health to 412 from 499.28, and his health growth to 64 from 71, while reducing the range of his spells. However, I also buffed his attack range to 600 from 550 to compensate for this extreme squishiness somewhat early on, and made him manaless. This last change I'm less sure of, but ideally it should allow Zilean to properly fulfill the support fantasy of not needing to factor in resource costs when deploying well-timed abilities, while his greater early vulnerability should let him satisfy his mage fantasy as well without becoming oppressive.
Active:Zilean throws a time-delayed bomb at the target location which detonates after 3 seconds, dealing magic damage to all nearby enemies.
Magic Damage: 40 / 60 / 80 / 100 / 120 (+ 0.2 per second of game time)(+ 100% AP)
If a unit is near a Time Bomb as it lands or has already landed, they pick it up and become the holder, causing it to detonate at their location at the end of its duration or upon their death.
Borrowed Time: If a Time Bomb collides with another, both detonate immediately, placing everyone in the explosion radius in stasis.
Spell shields will block either the collection of the bomb or the damage of its detonation.
Back when Time Bomb was a pure damage ability, it didn't serve a direct purpose for support Zilean, even though it allowed him to pressure through poke. When his mini-rework both changed its targeting paradigm and gave it a stun, it fit his overall theme a lot better. All things considered, this ability is in good shape, save for the fact that it's Zilean's only damaging ability on live and causes his damage to be difficult to balance (he ramps up a bit too hard from level 1 to 9, a fact made particularly glaring back when Time Bomb was point-and-click, but also falls off super-hard thereafter), while also not feeling like he's making that much progress after maxing Q out. This is where the unique time-based scaling comes in: early on, Zilean's damage would ramp up decently, though not to the same degree as it does now, and so would be easier to handle in lane, while inevitably scaling up very well past level 9 into infinity (and beyond). I originally sprinkled the rest of Zil's abilities with damage, but with just this ability, he'd be able to output impressive-looking damage at all stages of the game, and so I pared them down to pure time-based crowd control and utility.
RANGE: 300 / 375 / 450 / 525 / 600
COOLDOWN: 26 / 22 / 18 / 14 / 10
Active:Zilean marks the target unit, imprinting their location at the time of cast and causing their movement to leave behind a trail.
After 3 seconds, the marked target dashes back to their imprinted location, consuming the trail as they travel, and consuming it instantly and entirely if the dash is interrupted.
Borrowed Time: If the two trails intersect, both targets immediately dash back to the intersection and arrive at the same time, consuming Rewind in the process.
Rewind is pretty much the source of most of Zilean's problems: he's meant to be a good support as well as a mage, but it's a purely selfish ability that's locking him out of both a good support and good damage ability. While the ability is thematically amazing, it also carries little decision-making as an active ability, and mainly serves as a perfunctory bridge to QWQ comboes. Because of this, I think it would make more sense as a passive ability, and I moved it to his innate.
As a result, this leaves space in Zilean's kit for an extra ability, one that would allow him to express his time theme in an interesting manner while also projecting more outward power. With that in mind, I think it might be worth implementing an ability similar to a mini-Chronobreak, or X Marks the Spot in Dota, where Zilean could make both allies and enemies snap back in time after a certain delay. Imo, there's a lot of potentially interesting gameplay on both sides, as Zil could cast Rewind on attacking enemies to force them to back off, while still giving them a window of time to fight (and if they succeed within that window, they'd get a free escape), but could also cut off their escape if they're trying to run away. By contrast, using Rewind on an ally could allow them to make super-risky plays that would otherwise entail their death (it could also pull them out of a sticky situation when combined with Chronoshift), as well as provide them with a safety net that would let them act a bit more freely. Obviously, as a double-edged ability, this effect could backfire massively, though the recent appearance and success of abilities with huge troll potential means that would not be too big an impediment in itself.
Because the base effect wouldn't really scale per rank (increasing/decreasing the window per rank would carry unwanted tradeoffs, or at least tradeoffs that would likely not be worth having on here), I instead made everything else about it scale a lot harder. Because an effect like this could reverse ganks, it should have a massive early cooldown, a short range and a high mana cost, though all of those should improve with rank until Zilean would get to cast this much more freely later on, using it on allies as well as enemies, and not just as a pure self-defense measure (or ally defense in a duo lane). Another thing to note is that the target would remain targetable while dashing back, so they'd still be able to take damage and CC could pull them out of the effect completely.
COOLDOWN: 18 / 16 / 14 / 12 / 10
Active:Zilean creates a bubble of warped time at the target location which expands after a short delay and persists for a short duration.
Bubble Duration: 1 / 1.5 / 2 / 2.5 / 3
Time inside the bubble is slowed by 50%, including the movement speed, projectile speed, attack speed, channels, cooldown ticks, animations and effect durations of everything within.
Borrowed Time: Casting Time Warp within a deployed bubble pops it, speeding up time for everyone within by 100% for its remaining duration.
Time Warp in its current state is not particularly interesting, and while it does sort of relate to a time theme, it doesn't do so in a way that lends itself to the deepest gameplay or even fits Zilean himself (he's a floating, almost all-powerful time mage, not really a zippy grandpa). In order to change this, I think it would be worth making the effect more of an area control ability, allowing Zilean to manipulate time in select areas and complement the threat already established by his Time Bombs, as well as retain his movespeed-buffing abilities by potentially applying Time Warp to his whole team in one go. As with pretty much every other effect here, Time Warp is double-sided and is meant to let Zilean choose when to give his team a breather, which could backfire if, say, an ally were planning to capitalize on the element of surprise with an ambush. It would, however, give the Zilster additional leeway when trying to save targets, as he could pause battle just long enough to mark an ally, or lay a bubble right before an incoming deadly projectile.
COOLDOWN: 120 / 90 / 60
Active:Zilean marks the target champion, large monster or himself, causing them to revert to the health they had at the time Chronoshift was cast after 3 seconds.
If the marked target takes lethal damage, they are placed in stasis for the remaining duration.
Thematically, Chronoshift is amazing, and saving an ally (or oneself) from death feels hugely powerful and totally unique. On the flipside, however, this ability also carries some gameplay issues: in the way it's currently implemented, Chronoshift tends to feel like there's no point in trying to attack the marked target, since they can often end up being healed to even greater levels of health than before and doesn't feel too good for anyone involved, despite being tremendously strong.
In order to solve this, Chronoshift needs to feel rewarding and have a clear success case, without simply locking enemies out of affecting the marked target for an extended period of time. The first means of approaching this would be reducing the mark duration, meaning it would be, at worst, a not-quite-Intervention, and the second means is by making its use cases clear for everyone: the marked target will always find themselves with the same health as when they were marked, so they shouldn't feel timid about launching themselves into the fray in case the mark fades before activating, and enemies can outplay the ability by forcing the target into immobility while they are protected, allowing them to try again immediately afterwards.
So, what are your thoughts? When looking down at the comments, keep in mind that the above kit is in its third iteration, and the replies below may refer to a previous iteration: the first kit had the above innate and a prototype to the above Time Warp, though it was also super-weird in not the best way (it was a stationary zone that gave everyone, including Zilean, cooldown reduction and attack speed), and many of the other changes were fairly mediocre (Time Warp proper had a DoT slapped onto it while remaining point-and-click, for example); the second kit addressed a lot more issues, such as turning Time Bomb into a skillshot long before Zil received his small V5.4 gameplay update, and was generally pretty okay, but had the potential to improve a little further and receive more overall stuff after he got a stun on his Q (kit 2 also had a stun, but on his W, which worked like the above Time Warp, although both abilities were separate). Lemme know what you think of this version, and what you think could/should change!