This is my first champion suggestion and an idea I've been thinking about for a while. Suggestions are welcome and not everything is complete and can still change if there's some better idea. If you think of some appropriate lore, texts or item build, that would be appreciated too.
The direction I'm wanting to go with this champion is to have a tanky champion who has a good sustain and good damage, but always only one of the two. Because of this, I chose to make a tanky passive based on stacks, but having to sacrifice the stacks in order to perform your stronger attacks (and/or) heal yourself.
Kemaran's look and appearance should look like that of an evil slave driver and uses a short barbed metal whip as a weapon.
Kemaran is not an official champion in the League of Legends, but is a fanmade suggestion. 
|(Innate): Every 5 minion or champions that Kemaran slays, Kemaran gains one stack. Each stack increases Kemaran's armor and magic resist by
. Kemaran can have a maximum of 5 stacks. Stacks are lost upon death.|
Leash of Dread
|(Active): Kemaran extends his whip to it's full length to leash onto an enemy. As soon as it hits a target enemy minion or champion, Kemaran will send a surge of hate through the leash, slowing and damaging the target.
Cost: 60 / 70 / 80 / 90 / 100 mana
Magic Damage: 90 / 130 / 170 / 210 / 250 (+0.85 per ability power)
Cooldown: 11 / 10 / 9 / 8 / 7 seconds
Slow Percentage: 14 / 18 / 22 / 24 / 28 %
Curse of the Slain
|(Active): Kemaran calls upon the powers of those slain to curse target area for 4 seconds. Enemies within the area take damage while in the area and continuing to receive damage for 2 more seconds after leaving the area.
Cost: 75 / 90 / 105 / 120 / 135 mana
Magic Damage (Affected area): 25 / 45 / 65 / 75 / 85 (+0.25 per ability power)
Magic Damage (Outside area): 10 / 20 / 30 / 40 / 50 (+0.10 per ability power)
|(Passive): Kemaran feeds on the hatred of those who he has slain, which heals himself and grants a movement speed buff to those around him.|
Spell vamp increase: 3 / 6 / 9 / 12 / 15 %
Consuming Fear (Active)
|(Active): Kemaran unleashes the wrath of those he has slain to heal himself and add a movement speed aura.
Cost: 70 / 110 / 140 / 170 / 200 mana
Health Restored (per stack): 8 / 15 / 22 / 29 / 36 (+0.30 per ability power)
|(Active): Kemaran uses his whip to leash target enemy champion and moves dashes towards the location of the enemy dealing magic damage upon impact. Additionally, target enemy will be stunned for a short duration for every stack built up.
Cooldown: 135 / 115 / 95 seconds
Cost: 120 / 150 / 180 mana
Impact damage: 100 / 200 / 300 (+0.45 per ability power)
Additional Damage (per stack): 20 / 40 / 60 (+0.20 per ability power)