Ian (イアン) is a member of the Stationary Guard in Trost District.
Ian first appears in Ch. 5 after Trost District is breached by the Colossal Titan. He compliments Mikasa for killing a Titan that was attacking a group of evacuating civilians.
First Appearance
Anime: Ep. 5
(Source: Shingeki no Kyojin Wikia)