I suppose going to war with Valve would have been pretty bad PR. Still, Valve was forced to change a bunch of Dota characters' names and visuals so as to not infringe on Blizzard's IP.

Examples: Windrunner changed to "Windranger"; Pudge made to look less like a Warcraft "abomination"-style creature; Skeleton King renamed and remodeled to "Wraith King".

> Meanwhile, DOTA2 is a thing...

After an IP battle that was settled out of court.[1] Valve also does not use any of Blizzard's assets in Dota 2.

[1]: http://www.engadget.com/2012/05/11/blizzard-and-valve-settle...