Backups/Towers for PVP

I have faced several people in the past two weeks who have had like 2 - 6 backups when the main thing is defeated in the first position. How do you do that cause I would love to create those backups/towers for when I am in the PVP arena.

Not sure what you mean with towers, however, backup is a talent of the dark tree (but there’s more) so to get it you need lvl a class cough, thief, cough, then pick those talents.

You cannot use back in arena tho seen in there classes dont work, neither flags and weapons will be without upgrade.

There’s also weapons that summon, get the jar of eyes asap, seen it fill a team where only the hero was alive in 1 turn.