Steak is Niche's "pet" and emergency food supply. He followed her from the Love Someone Down freak show after she destroyed it. He is usually seen traveling on her head, very rarely moving from his perch even while she is battling Gaichuu. He has the ability to sniff out the weak spots of Gaichuu, allowing Lag to fire his Shin Ganjuu at the weak spot, killing the armored insect.
Niche has remarked that Steak would taste delicious (hence his name). Steak seems to have accepted his fate as a future meal and appears to have meekly submitted to Niche's (interrupted) attempt to cook him.
Steak may be the last of the Kapel Meister, a species that once co-existed harmoniously with the Spirit Insects, and was thought to be extinct.