According to my friend, the procedure is as follows:
- Have a team member cast Haste on the sword dancer
- Activates Shriek
- Casts Magic Missile
- Casts Sanctuary
Next round
- Casts Spirit Guardians
- Runs through the enemies (Sanctuary drops)
- Shield then protects from hits
There are now no more problems with Sanctuary. Sanctuary is only there to be able to break into the ranks of the enemy without danger

I didn't know that Spirit Guardians is selectable with Bard (10), so thanks for the great hint

As far as the fighter topic is concerned:
- Sleep 100% critical damage
- Hold Person /Hold Monster 100% critical damage
- Various potions and other spells
The 5 percent of Champion is more than negligible. The best example of this is Paladin 6 / Sorcerer 6