Can Sett's effect be used during defense when being attacked, and how does his buff/might conversion work with conquering?

Ruling: Sett's effect can only be used on your turn outside of showdowns because it does not have ACTION or REACTION keywords. When you conquer (either attacking or defending), Sett gains a buff. On your turn outside showdowns, you may remove his buff to give him +4 might.

Sequence:

• Sett gains a buff when he conquers (attacking or defending)
• On your turn, outside of showdowns, you may remove the buff to give him +4 might
• The +4 might lasts only for that turn
• If Sett conquers again, he gains a buff back

Nuances:

• The +4 might is temporary and ends after the turn it's activated
• Conquering works both when attacking and defending to grant buffs