Giant Hyena
Giant hyenas are as the name implies; huge hyenas that could swallow even the largest Sentients whole if they so chose. Despite their size and ability, they have never been known to harm anyone and prefer to keep to themselves.
Though they are placid to visitors to their home, Hyena Island, they do not allow anyone to stray too far off the coastline; simply picking them up and placing them back on the beach when they do.
They cannot, or perhaps simply do not, speak any language other than their own. The way they communicate is very much recognisable as a verbal language and was the original indication of their intelligence.