Ramming Pulverizer
I have all three at 4* 3.60 or higher. But poor Gormek is the only one left at 4* 3.60 .
Blue glass cannon
I have a Grimm 4*+7 and a Grimm 4* 3.60 .
Blue ( strong versus red ) Ramming Pulverizer really helps for the Barbarian quests ( both have triple red Bosses ), especially Survival trial which has triple red Bosses and red mobs ( use emblems to get more emblems ).
Good Classic blue 4* heroes are limited to Grimm and Kiril. I would use multiple 4* 3.60 Grimm ( and have ) but I tend to run one Kiril ( 4* 3.60 or 4* 4.70 or 4*+1 Kiril. sorry Kiril, Proteus is also a Wizard ). While purple 4* Heroes and red 4* Heroes have a large number of good to insanely good heroes ahead of Tiburtus ( Rigard, Proteus ) and Gormek ( Boldtusk, Scarlett, Wilbur, Guardian Falcon, etc. )
Grimm’s defense stat is lower than Gunnar’s defense stat. Instead Grimm has a huge attack stat which does nice matching/ tile/ board damage even when Grimm 4* 3.60, or 4* 4.70, is dead.
Cascade squad
Click for Wu Kong plus Ramming Pulverizer
My Grimm 4*+7 works well as a blue hero for a the original, insanely over powered, Wu Kong Cascade squad. Use ascension items to get more ascension items.
Wound
For neutral damage, Barbarian Grimm does the most matching/ tile/ board damage for maximizing Wound talent.
Pierce
Click for Gormek verus Tiburtus
After Grimm, I used to like Gormek better than Tiburtus because Gormek was strong versus Green bosses while Grimm was weak. But since Gormek is the same class as Grimm and both lack Pierce, I really like my recent Ranger Tiburtus 4*+9. Especially against yellow centers in raids.