There have been Warhammer 40K games on Android before. They have not been particularly good, mostly because they simply slap the license on top of an existing mobile game style and hope the dedicated fans will spend some money. Not so with Warhammer 40,000: Space Wolf. Not only does this game come from HeroCraft, a developer that can generally be relied upon to create decent games, it's a top-down, turn-based strategy title. What an idea!
Space Wolf is closer to a tactical strategy game than a straight-up board game adaptation, but that makes sense in the context of the medium. Anyone who's played Final Fantasy Tactics or XCOM will be familiar with the grid-based layout. The game also relies on trading cards for attacks and power-ups, which enables the developers to use the rather depressing currency system and the requisite $100 in-app purchases. Warhammer fans might be able to forgive that - they're used to being nickel-and-dimed for figures and such, after all. Alternately they can simply grind through it.
Thankfully HeroCraft hasn't skimped on the multiplayer. Three on three versus battles are available in a sort of mix between the MOBA and tactical game formulas, and the game already has seasons and leaderboards set up for serious players. Check out Space Wolf if you'd like something a little more authentic than a Warhammer endless runner.