Hello,
So today I decided to powerpass my alt character which is Deathblade, after doing that the class surprised me a lot and so I decided to make it my main character. I changed her to Main in the character selection menu, but when I play her I don’t have the Main Quests. What am I supposed to do now so I can progress on Deathblade character? Am I supposed to reach 460 ilv on my previous main(Bard) and then I can make Deathblade my main once again?
Thank you in advice 
Your main questline should still be there.
Bring up the quest journal window by typing “J” .
On the “In Progress” tab, tick the box of your Guide questline.
That should now appear on your active quest windows on the right screen.
To my knowledge the Powerpass completes Every Quest on the Main Story continents up to and including shushire. It also gives you a certain Itemlevel 302-340 or something , you should have received a quest to upgrade to 460. If you did your power pass right after Vern you effectively skipped a whole continent + a lot of side and rosterquests if you did not do them on your main.