Bombard, Shadow form or defenses

What to train next? Bombard would synergise with shadow mimic. Shadow form looks like it would be okay defensive buff, but it drains. +3 invo aptitude helps with getting it online, but not sure how much invo I need. Cactus giant seems to be doing okay so far so could focus on training defenses and let cactus giant handle it until I have found more spells or other direction giving loot to better plan where to go with my character.

Morgue: Dungeon Crawl Stone Soup version 0.31-a0-1597-ge7908ec95f (webtiles) character - Pastebin.com

Shadow form is an amazing “oh s–t” tool IMO. So I’d certainly try to get it online before too much longer, given your invo aptitude.