The 5th gate is the Limit Gate its located in the abdomen. I gain +30 taijutsu damage and my speed increases x3.5 when I open this gate. However, I take 15 damage ):
Due the increased blood flow. But that actually happens at third GAte release, nothing in partiuclar happens during Fifth Gate other than increased power and speed, LOL. Okay.. Break the damned Gate, and let's get over with the activation.