I found this on another web site and thought I’d post it here so it be easier for ppl to know the requirements for this achievement 👍 good luck everyone 👍 and hope this helps y’all out
As you progress through the online levels, you will have the chance to fight the three main bosses again at different tiers. In order to earn the trophy, you must defeat them all on their tier 3 fights. To do these fights, you must be the following level online:
Kruetz – Level 10 for tier 2, Level 40 for tier 3
Cargal & Kilnor – Level 20 for tier 2, Level 50 for tier 3
Risryn – Level 30 for tier 2, Level 60 for tier 3
When you defeat a boss on tier 2, you will be awarded their chest piece whilst tier 3 will give you their masks. Be warned - the fights are much more difficult at these levels. The bosses are a lot more aggressive, precise and punish you massively if you try to barrage them with attacks. Be patient, take your time and you will earn this trophy in good time.