PoB

Honestly picked an awful map to showcase the build, it's a lot more visually exciting (and funny) in wider areas and with bosses who aren't stuck on the side of the arena. So many explosions when 4 ballista + siege cascade is firing off that you can't see shit.

Not saying it's a great build, but it has been cruising through the game without any issues so far, and been a lot of fun with the screen constantly blowing up.

Siege cascade can one-shot most white/blue packs by itself, I just drop 1-2 ballistas while I'm running through the map to help out and drop the full 4 for rares or bosses. The ballistas stun very effectively, which enables the bonus damage against immobilized for siege cascade. This synergy will only get better when I further ascend and get the heavy stun related nodes on the titan tree.

Convert to lightning to take advantage of shock and the "30% chance for damage to be lucky" node. Honestly, I made that choice not knowing that node was nerfed from its 0.1 version, and I'm not sure the lightning convert is necessary or worth it anymore. It may be better to scale fire and just use three dragons to get shock, that is something to test.