Research: speed increase
Training: speed increase
Troop Size: increase
Ironclaw is definitely one you should level to 131. All three of his troop skills are useful to anyone.
I often see this guy in Arena. He hits for quite a bit of damage targeting a foe, and that foe’s adjacent allies. He reduces the target’s Heal rate for 50% and it cannot be dispelled.
Combined with a hero like Eve that can increase the Rage regeneration of allies, Ironclaw’s Metal Ripper becomes insane.