Ta Sai Tho is the patron deity of Clan Tel'Dora. Then is saying "leaves" because Ta Sai Tho takes the form of a coil of aquatic plants constantly moving against the currents.
Then is pronounced with a soft “th” like “threw” and “thought”, and rhymes with “Hen” and “When”
I wanted Then's stealth effect to be subdued and hard to notice because I hate it when stealth effects are portrayed in media by methods that are visible to the viewer's naked eye. Also so he wasn't noticed too early. :P