Is Thunder an Elemental keyword? Would it count for unstoppable power?
Osano-Wo's Rebuke and Unstoppable Power
A topic from AEG's L5R CCG Rules forum, copied for Oracle of the Void from a copy of the forum saved in October 2015, so pages it didn't save are missing. Players' names are left out; the rules officials are named. Rulings are as they stood on these dates; later rulings, the rulebooks and the Rules Archive may differ.
No, per Glossary, Element keyword: "Any of the following five keywords representing the mystical elements: Air, Earth, Fire, Water, Void."