Base health regen: Briar is the only one of 173 champions at 0, and Dr. Mundo, whose passive brags about regen, ranks 112th at level 18

The last line of Dr. Mundo's passive says he has significantly increased health regeneration. But look up Mundo's health regen in ddragon's base stats and you get 15.5 at level 18. That's 112th out of 173, below the 17.4 average. All of Mundo's regen is stacked on the passive, and the raw number is below par. That made me curious, so I lined up all 173 champions.

What health regen is

It's the health you get back over time even when you're not fighting. ddragon's champion data has a base value per 5 seconds and an amount gained per level. I compared the level 1 value with the level 18 value, which is the base plus 17 levels of growth. Source: Riot Games' official ddragon data.

The average is 6.3 at level 1 and 17.4 at level 18, roughly a 2.8x increase. The most common base value is 5.5 with 28 champions, and the most common growth is 0.55 with 46. That seems to be the standard template.

Top and bottom at level 18

Rank	Champion	Lv1	Lv18
1	Vi	10	27
2	K'Sante	9.5	26.5
3	Darius	10	26.15
4	Gnar	4.5	25.75
5	Braum	8.5	25.5
5	Sejuani	8.5	25.5

Rank	Champion	Lv1	Lv18
168	Lillia	2.5	11.85
169	Aatrox	3	11.5
169	Swain	3	11.5
171	Rek'Sai	2.5	11
171	Soraka	2.5	11
173	Briar	0	0

Vi's 27 at the top is about 2.45x the 11 of Soraka and Rek'Sai, the lowest apart from Briar. At level 1 it's Darius and Vi's 10 against Soraka and company's 2.5, a 4x gap. It's a little funny that Soraka, the poster child of healers, barely heals herself (she literally spends her own health on W to heal others, so that makes it worse).

Briar is even more extreme: 0 base and 0 growth. Her passive says it plainly: she lacks innate health regeneration. Her only healing comes from the bleed her attacks and abilities apply. If she doesn't hit something, she gets nothing back. Pretty bold design.

Gnar goes from 141st to 4th

Gnar moves the most. His level 1 value of 4.5 ranks 141st of 173, but his growth of 1.25 is the only one above 1 among all 173. By level 18 he reaches 25.75 and 4th place. That's about 5.7x, growing at more than twice the average rate. Irelia also climbs from 159th to 65th, and Nunu & Willump from 137th to 61st.

The biggest faller is Singed. He's 5th at level 1 with 9.5, but his growth is a standard 0.55, so he drops to 57th at level 18 with 18.85. His 1.98x multiplier is the lowest of all 173. Garen falls from 35th to 91st, and Mundo from 60th to 112th. If you judge regen by early numbers alone, the late game might not match your impression.

Mana didn't matter

I wondered whether champions without mana get extra regen, so I split them. The 145 mana users average 17.40 at level 18, the other 28 average 17.56. Less than 1% apart. Regen clearly isn't tuned by resource type.

Takeaway

Base health regen differs by up to 4x at level 1 and about 2.45x at level 18. But judging a champion's staying power from this table alone is risky. Mundo keeps his regen on the passive, and Aatrox's passive says his empowered attack heals for the same amount as its bonus damage. Briar goes all the way, zeroing out natural regen and shifting it all to bleed healing. The champions with the strongest healing put it in their abilities, not their base stats. The stat sheet is just the starting point, and that's my takeaway this time.

The self-proclaimed regen pro Mundo is 112th on the stat sheet. The real healing was hidden in the passive