User blog comment:Willbachbakal/(Champion Rework) Singed, the Mad Chemist/@comment-4914725-20131031213045/@comment-1330314-20131103014906

That's actually something I talked about in the page above: Singed gaining health from mana means that he can easily become stupidly tanky while simultaneously getting rid of his mana problems. I wanted him to have more utility and damage to bring to fights while allowing enemies to still be able to damage him in the late game, which is currently very hard to do due to the combo of his innate tankiness, mobility and anti-chase mechanics.

Also, just to point this out, 's innate also gives him bonus attack damage.