Visitor Event Stage 3

For the bomb stage theres a number of ways to do it however, easiest being bringing an Aran to do the job with tempest. One of the slowest ways is grab 2 or 3 mages and have them spam aoe all over the map and warp thru the dimension whenever a bomb appears. Its also possible with using fire mage to mist the dex aliens in the other dimension while everyone else weaken the str aliens and having the mage finish off dex aliens later with a meteor. Letting your attackers take each platform would help ease out the kill speed since they would die close to the same time. You can also weaken the dex dimension side yourself if you don't have mages around and focus on str dimension first. Well, the list goes on, I think theres loads of suggestions, methods, and/or guides around that people made already for the visitor cube.

When it comes to the mage room (the person that dispels you and casts explosion), its mostly DPS and some cooperation involved since you have to focus on the mage mostly and theres 2 of them keep in mind the dispels are a pain for jobs that need to recast a lot of slow buffs (lets say DBs for instance, I hate how long it takes me to recast my buffs and I get nerfed by almost 3 times my dmg when I get dispelled) and if you brought any DKs, they need to really pay attention to the dispels (which is easily depicted by a grey rock with red/orange borderlines). The last boss doesn't take too much strategy but you can avoid the explosions after getting sealed if you get there though.