Guthan's the Infested is one of the six Barrows brothers, the guthan's armor is very strong in PvM. This equipment is good for PvM due to its ability to drain enemies hp & add it to the players hp who is using it. This armor was more known for killing NPC's at Fight Caves for tokkul. Guthan's is one of the more defensive barrows equipment.
Guthan's armor effect is healing over time. The effect works well on various types of bosses or npcs. Like most other Barrows equipment, this is used for PvM mainly. The effect can be useful when soloing a boss, or just generally fighting a hard boss.