Ethnos
Can a Merfolk bonus marker go in any Kingdom, regardless of your band's size?
The Merfolk section allows the bonus marker anywhere, whatever the band size.
- Ethnos rulebook · Rulebook · Tribe of Merfolk
Yes. Reaching a marker symbol on the Merfolk track lets you place another Control marker in any Kingdom, regardless of the size of your band, even one where you already have several markers.