Doctor Gustaf VanHowzen is a level 48 first aid trainer located in Foothold Citadel on Theramore Isle, in the contested territory of Dustwallow Marsh. He teaches how to create Heavy Mageweave Bandages at 240+, Runecloth Bandages at 260+ skill and Heavy Runecloth Bandages at 290+ skill for free.
He starts the quest [45] Triage (First Aid).
See List of Dustwallow Marsh NPCs.