Casting HBO's Green Lantern Corps

Kilowog is a character whose on-screen creation would stem primarily from CGI - making any physical qualities an actor may have redundant.

The voice then is what is most important.

From Kilowog's dialogue in the comics, it is clear to see that the character has a very distinctive voice pattern, just like Wolverine. Previous movies and animated shows have done a decent job in casting actors that were able to convey this speech pattern, yet it seems unlikely that Warner Bros. or HBO would simply bring one of those actors back, so someone new is needed.

That new person should be Ving Rhames.

Listen to Rhames' voice and it is clear that it has the qualities needed to accurately reflect Kilowog's speech: the tone, the pitch - it's all there. Why look anywhere else?