leader
Ἐς δὲ τὰ ἔσχατα νουσήματα αἱ ἔσχαται θεραπεῖαι ἐς ἀκριβείην, κράτισται -> For extreme diseases, extreme methods of cure, as to restriction, are most suitable.
Corpus Hippocraticum, Aphorisms 1.6.2
guide: P. and V. ἡγεμών, ὁ, or ἡ, P. ἀγωγός, ὁ; see guide.
chief: P. and V. ἡγεμών, ὁ, or ἡ, προστάτης, ὁ; see chief.
ringleader: P. and V. ἡγεμών, ὁ, or ἡ.