My first champion idea: Xor'Khan, the void general.

Overview

Region: The Void

Role: Top

Class: Tank/Juggernaut

Xor’Khan is a voidborn created by the watchers to destroy all of creation. In the void’s war against Runeterra, Xor’Khan fights at the front lines, destroying countless powerful foes, marking himself as a formidable enemy.

His role in the game is a late game hyperscaler who slowly grows stronger by just existing. However, he can speed up his scaling by taking damage from enemy champions. However, if he dies, then he loses all of his progress. He is meant to scale into an unkillable tank in the late game while having an extremely risky playstyle.

Stats (Lvl 1-20)

Health: 600–2684

Attack Damage: 60–120.8

Armor: 33–77.8

Magic Resist: 22–50

The Void General

Innate: Xor’Khan gains 2 progress every 3 seconds, capped at 100 progress. Every time he loses 20% maximum health from an enemy champion, he gains 10 progress. Upon death, all progress is lost (Progress is shown below health bar).
Innate – Growth: Upon reaching 100 progress, Xor’Khan can press the minion button, channeling and rooting himself for 5 seconds. After 5 seconds, Xor’Khan consumes all progress and gain a stack of Growth. The channel is interrupted if he takes damage, but the rooting remains. Upon death, all stacks of Growth beyond Xor’Khan’s level are lost.

Innate – Adaptation: Regenerate 1%-4% (based on level) bonus health every second. Regeneration will pause for 5 seconds if Xor’Khan takes damage.

Piercing Strike

COOLDOWN: 9/8/7/6

Passive: Xor’Khan gains bonus attack damage (+0.4% bonus health per stack of Growth).

Active: Xor’Khan thrusts his bone blade in a target direction, dealing 75/150/225/300 (+5% maximum health +100% attack damage) physical damage to enemies hit and apply on-hit effects.

Reinforce

COOLDOWN: 16/14/12/10   COST: 15 Progress

Passive: Xor’Khan gains 15 armor and 7.5 magic resist per stack of Growth

Active: Increase armor and magic resist by 50% for 2 seconds, as well as gaining a shield absorbing 50/80/120/170 (+15% bonus health) damage.

Warp

COOLDOWN: 20/16/12/8   COST: 65/50/35/20 Progress

Passive: Xor’Khan gains 2% tenacity and 1% slow resist per stack of Growth

Active: Xor’Khan blinks toward the target direction by a small amount, gaining 10/15/20/25% bonus movement speed that decays over 4 seconds.

Ultimate Lifeform

COOLDOWN: 90/80/70   COST: 1/1/2 Growth

Passive: Upon reaching 17 stacks of Growth and maxing out this ability, Xor’Khan’s Adaptation cannot be paused.

Active: Xor’Khan curses an area, slowing all enemy champions by 30%. After channeling for 1 seconds, Xor’Khan becomes untargetable, and teleports to the center of the cursed area after 3 seconds. Slowing all enemy champions in the area by 70% for 1 second. Enemies within the epicenter are feared for 1 second and take 150/300/450 magic damage. While the effects of Growth are amplified by 5/20/35% for 8 seconds.