I just thought I'd post this for no reason (cause' I'm like that). Criticize below (this one is a bit OP), and enjoy :D
Nest, the Relentless Swarm
The Swarm was first discovered during the Rune Wars, when a crystal mine broke through into a massive cavern. The mine was rapidly overrun, and the surrounding lands razed. Powerful spellcasters reactied quickly to the threat, and blasted the area with immense energies before completely sealing off the mine using magic. The threat was gone for now... but something had been awakened. Years later, the ground spilt open and the barrier was cracked, and once again the Swarm had to be blasted, and sealed off before it could spread. These "incursions" into the upper world happened time and time again over the years, until finally, after the creation of the League, it was agreed that a firm resolution to this problem had to be found. Some of Valoran's strongest warriors went down into the mine, and began purging the swarm. It was a seemingly simple task at first, but then they began to encounter traps. The bugs set ambushes, made calculated attacks, as if they were intellingent. The warriors realized that their only way out might be to negociate, and it was then that they found Nest.
Nest is, quite literally, a nest. This hive, built by the swarming bugs, had over millions of years become so complex it gained a life of it's own. A bit like a wasp's nest on legs really, except intelligent and with control over the Swarm. The warriors were able to make a deal: They would be able to escape from the mine with their lives, in return a limited portion of the "upper world" would be given to the Nest for it to roam. The deal worked for both sides: the nest got it's territory, the warriors kept their lives, and the summoners didn't have to keep the Swarm in check. However, not all was well. After razing it's perscribed area, the Swarm hungered for destruction. So the Nest once again negotiated, and found it's perfect home: A "League of Legends" where it could rip apart the strongest fighters of Runeterra time and time again.
Nest is a very odd champion that mostly relies on summons and map control...
Passive: Swarm Hive. Nest has no autoattack. Instead, she fires out Swarms of bugs which attack her enemies. A Swarm is very weak, and lasts for 5 seconds (doing DoT to it's target) before it dies (if it's traget dies it will attack a random nearby enemy not being attacked by a Swarm) Nestcan create lots of Swarms by switching targets rapidly, but there is also a major disadvantage: when an enemy champion walks through/over a Swarm, it dies. The other option for Nest is to stay on the same target: she will continually Reinforce the Swarm attacking the target, increaing its Health and duration. When a Swarm is reinforced 5 times, it can no longer be simply run over by enemy champions (in short, kill the swarms when she first makes them!). When a Swarm is reinforced 10 times, it grows in size, and gains boosted damage and range. A swarm can be reinforced up to 13 times.
Active: Outpost. Nest creates an Outpost at the target location. The outpost contains 3 fairly strong Hunter Bugs, which will attack enemies within a certain range of it (a bit like a monster area), and respawn from the Outpost 20 seconds after they die. The Outpost lasts for 3 minutes, but is visible and can be destroyed fairly easily if targeted, stopping the Hunter Bugs from respawning. Leveling up this skill increases the health and DPS of the Hunter Bugs.
Active: Harvesters. The Active targets an area: Nest sends out some Harvester swarms (unattackable, unlike normal Swarms) to gather around an area for her, which swarm over bodies, dealing a small amout of physical damage over 3 seconds. When they return, she gains a temporary buff in Mana Regen and a heal, which are larger the more enemy Minions and Champions were affected by the spell.
Active: Frenzy. This ability can only be used when Nest has been Melee attacked within the last 5 seconds: The bugs inside Nest are rumbled, and go crazy, swarming in a close area around Nest. The first 3 enemies they encounter take some Magic Damage, and get a level 5 Swarm sent after them (Nest has to move close to an enemy for them to "encounter", and she can't control which ones they go after). This Frenzy lasts for 10 seconds or until it affects 3 enemies.
Ultimate: Unleash. A Toggle ultimate. Nest roots herself into a spot (this takes a couple of seconds) and unleashes the full fury of the Swarm. Tons of bugs come out of her, and deal huge DPS in an area around the rooted Nest. This area of destruction exapands gradually, however after the first 4 seconds Nest starts losing 5% of her health per second as too much of the Swarm leaves her. When the toggle is deativated, Nest uproots herself (the health loss stops as soon as she starts uprooting, the massive DPS zone continues, but shrinks quickly back to her as she uproots). Enemy champions will have no health regen in the affected zone for the next 3 minutes.