The official Stradigy guide says after he becomes available you can recruit him "at any point in the game".
So Just go to storm coast and he should be there ^^
"After addressing the clerics in Val Royeaux, speak to Krem standing outside the Chantry in Haven. He invites you to come to the Storm Coast and meet his commander, Iron Bull—this unlocks the quest The Captain of the Chargers. Before you can go to the Storm Coast, you must first scout it on the war table. Once at the Storm Coast, help Iron Bull and his Chargers eliminate a group of Tevinter mercenaries. Afterward, Iron Bull offers his group’s services to the Inquisition."
"Iron Bull can be recruited at any point during your adventure after this. "
No that does not apply when in Skyhold. You need Krem to kick it off but he does not appear. Its a design flaw in the game.
Was anyone able to figure this out? Could it be a bug since the mission still exists in my Inner Circle journal.
