Welcome to Librarium Online!
Just curious...would it be possible for a lone farseer on a jetbike to use Mindwar on an enemy unit then use his assault move to join a jetbike squad before the opposing players turn?
Was thinking this might be rather beneficial in certain circumstances if it is at all possible. Thoughts? Thanks in advance!
nope, you cannot join or leave a squad except in your movement phase. I remember checking the exact same thing for my Autarch. you can however use the assault move to hide behind the squad giving you a cover save, even though he has runic armour so it's not necessary. I'd hide behind some trees or something.
Fortes Fortuna Adiuvat