I defeat his first form easily, but when the second one comes there is a point in which my pets stop attacking. Is there any issue with this boss?
Yea it's one of the countless bugs the company doesn't care about fixing them. Melee pets do not attack him, you need ranged pets like the nymph.
Yeah, I have a nymph too, but at some point she also stops attacking :(
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Yes, it's a stupid bugs that existing since Ragnarok released till now. Game dev team seems doesn't care about to fixed it no matter how many players reported.
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My wolves were unable to hit Surtr during one of his phases, namely when he was to the right of the portal. All other phases were fine.
-> it's duo to terrain impact conflict between wolves or any melle pet versus the the boss, as they try to attack him and they cant reach, it's during the 2nd phase when he appears on right side.
Get into melee range. They will follow you and be able to attack. When they attack, you can move away.
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Recommended Resistances: Fire and Physical