Helch starts under the water. Kill the tenticles that are up. When they die, it will rouse Helch, he'll drop a pillar across the front bridge, and the back one will fall away. Pick a set of new tentacles, kill them and first pillar to Helch will drop.The remaining pillars are now pulled down at 75% health, 50% health, 25% health.Plan ahead of time what Helchgam morale you are going to run off the bridge at (sometime before reaching the pillar vanishing). If anyone gets rooted on the bridge, stop damaging Helch until everyone is safely off the pillar. Have range finish off the percentage until he drops the pillar.Anyone not ranging Helch should hide behind pillar-stump.Repeat until on last pillar. Kill him.