Warning, this and the next 3 chapters are summaries of the past chapters.
Chapter 11
The High Guardian, now nearly "Grand" with 8 Tomb Hearts, overpowers Sett. He uses its weight against it, aiming for wine-green flames, but its Axiom of Water douses them. Zainah's Song of Playfulness briefly distracts it, allowing Sett to trap it in the coffin momentarily. It breaks free, forcing Sett to strategize anew.
Chapter 12
Fully evolved to Tier 1 "Grand," the Guardian dominates. Sett lures it into a passage with ostrich mummies, burns them with Zainah's song (Limitless Evolution reaches 100/100, granting a useless skill), and escapes with Zainah and Zarah.
Encountering another Tomb Raider (2 Tomb Hearts), Sett kills him as the Guardian attacks, evolving to Tier 1 "Grand" (9 Tomb Hearts).
Matching its strength, Sett stomps it to death with better technique, ending the threat.
Chapter 13