Marinche exerts significant influence over The Doctor, frequently manipulating him into actions he might otherwise avoid during their pursuit of the Cities of Gold. Her motivations appear driven by wealth, demonstrated through a readiness to betray companions for gold. This treacherous nature aligns with her historical inspiration from Malinche, the Aztec woman who aided Spanish conquistadors against her people. Her role becomes prominent during expeditions to Olmec territories, where she and The Doctor meet their end amid the destruction of the Olmec base.

Marinche appears across multiple seasons, alongside The Doctor in Season 1 and with Isabella Laguerra in subsequent seasons.