At the WQ Fury Road in higmountain, you get a crystal from Shardmaster Ufrogg that transforms you into an Ambershard and phases you so you can collect crystals.
But if you run through the cave to the back and kill the NPC/miniboss Wrathshard that is usually for questing normally it will break you out of phase but stay transformed.
Once in the normal phase all the abilities hit extremely hard, usually for about 2.2mil, if you run to the entrance you can see all the players coming to complete the quest... and one shot them if they are opposite faction... and receive Honor, you can also kill the mobs that are almost instant spawn for farming with a friend possibly.
not tested properly but I think while transformed you also appear friendly to both factions, never been attacked at all.
I managed to drop the quest and replicate a the above 3 times, it didn't work once, so may be a bit of perseverance needed to get it to work.
feel free to remove/move to elite to preserve - this has been active for a while but wanted to test again, once the quest came up again,
Edit;
Seems that dropping to the lower level of the cave, and going to the left of the ramp up getting slightly stuck between the small rock and the ramp will take you out of the phase, I have just been trying again to replicate, miniboss wouldn't show but got out of phase while still transformed this way reliably 4 times in a row.