Freya's trance changes her jump ability. If Freya jumps while in trance, she throws seemingly a rain of spears at the enemy, and she will continue doing this every turn until her trance is over. Since she doesn't come down, she won't be affected by the enemy's attacks. This will happen even if you select her to jump while she is not in Trance, and she is hit causing her to go into Trance. It's very useful, though usually her attacks get weaker as the Trance fades.