Mariner class series

The Mariner class series is the default class series available to the Mercury Adept Piers. Piers becomes this class series when he either has only Mercury Djinn set or no Djinn at all. This class series is unique to Piers; Mia, the other Mercury Adept, is a healer rather than a warrior and has her own default class series, the Water Seer class series.

Analysis
It is widely argued that the Mariner class series is better for battle than the Water Seer class series, while the latter is better at healing.