I need about 3 to 5 people to defeat these types of strong monsters. Is there a group that I can join? I am after Achievements so any suggestions or advice would be helpful. This community has been extremely helpful.
You have several options, if you don't already know people who would be willing to help (friends, guildies etc.)
1. Just wait for other people to show up. Sooner or later a group of boss-runners will happen by, but depending on time of day this may prove inefficient. Sometimes you just get lucky.
2. As Casparian said, ask for help in zone chat. Say that Boss X is up, so that people know where to go, and more often than not a few people will join you.
3. Similar to the above but slightly more organised, ask in zone chat if there are any groups doing boss runs. This is done best during prime time, but if you find one, it's a good and efficient way of clearing all of the achievements in that zone.
At high level, depending on your skills and gear, some bosses can be soloed if you know the mechanics. Really good players have soloed them all or nearly. For the average player however, at least 1-2 other people will almost always be needed however for most of them.
Usually if you type in chat "anyone for <boss name>"? You'll get a couple of people to help.
Alternatively, wait until you have high CP and good gear and you can solo them.
7-day PVP campaign regular 2016-2019, Flawless Conqueror. MagDK/stamplar/stamwarden/mageblade. Requiem, Legend, Knights of Daggerfall. Currently retired from the wars; waiting on performance improvements.
You cannot defeat skull and bone monsters! you are so boned!
Playing your character the way your character should play is all that matters. Play as well as you can but never betray the character. Doing so would make playing an mmoRPG pointless.