My Ironjawz are led by Badrok Ashbringa - a tough Warboss who strides into battle on his Mawkrusha, Cinda da Eva' Living. Rumors among his "Burnas" (his boyz) is that Cinda is immortal and never really dies. In reality, Badrok just names all of his Mawkrushas Cinda.
My Gloomspite Gitz, which I typically run with either Squigs or Spiders, are led by Niznak Danfinga, leader of the Dank Ridaz'. He was a given a prophecy by Da Bad Moon that his faction of Gloomspite would be the ones the claim it as their own and supplant Skagrott as the leader of the various Gloomspite clans. In his prophecy his was given a vision of a massive spider/squig hybrid that was able to bounce to the moon and tether it using its webbing, allowing him to claim it. As a result, he has been engaging in breeding experiments with spiders and squigs of all sizes to make the hybrid creature. So far he has had a single success and currently rides it as his personal mount while leading his gitz.