The Mass Effect trilogy was a science fiction epic that followed Commander Shepard as they travelled the galaxy trying to stop the apocalyptic Reapers from wiping out all life in the known universe. Shepard had help from an assortment of squad mates that would accompany him on different missions, from other humans to different alien species such as proud Turians, noble Asari or battle hardened Krogans.
Mass Effect had a rich lore with each species having long and entangled histories that only added to the scale of the story being told. This was no different with the characters themselves. In addition to being shaped by the past of their people, Shepard's crew had their own layered backstory that fed into who they were.
The trilogy boasted the concept that player choice mattered meaning some of the characters on this list could've been in all three games or only one. The trajectory of the narrative would shift depending on the player's choices which means that depending on the circumstances, a lot of these characters could turn out very differently per playthrough.
Each squad mate was unique and developed and would evolve as the story progressed. The range of character development on display was akin to a sprawling television series spanning several seasons. This means the characters were incredibly written and made the Mass Effect games all the more unforgettable.