Nebula: Shattered Pillar Zenith Found
Champion size when encountered: Frigate/Destroyer
Factions: Shattered Pillar (Zenith) vs Neinzul Astrids vs Dark Spire
Tactics: quite variable. If encountered early, escorting friendly bombers is probably the right route. But if you can, destroying on of the enemy large starbases early (bypassing the small ones) is one of the best tactics.
Reward: Shattered Pillar Fabricator: +100,000 energy, allows construction of: 3 Palisades 3 Bulwarks 1 Monolith
Zenith hull Experience based on time; faster=better.