The character is a drell, a race of extraterrestrial reptilian humanoids who form a sociopolitical alliance with the hanar, a sentient species of jellyfish-like entities.

A notorious professional assassin, Thane may be recruited by Shepard in the planet Illium for a "suicide mission" to stop the abduction of human colonists by a mysterious species known as the Collectors.

Thane makes further appearances in two issues of the Mass Effect: Foundation limited comic series, which take place prior to the events of the trilogy.

[2][3] Thane was raised on the ocean planet of Kahje, the homeworld of the hanar, a species known for their strict adherence to polite speech and proper etiquette.

[4] A few centuries before the events of the original Mass Effect trilogy, the hanar evacuated a portion of the drell species from their dying homeworld Rakhana and transported them to Kahje.

Instead of adopting the hanar worship of the Protheans like some of his brethren, Thane is a devotee of the old polytheistic religion of his species, and spends much of his time in prayer and meditation, even within his work.

[11] Cassidee Moser, writing for Gamesradar, called Thane's prayer to the drell deity Amonkira[13] a summation of his humble and loyal personality.

While the relationship itself does not carry forward into Mass Effect 3 due to the conclusion of his story arc, the player has the choice to spend private time with him at the Citadel hospital as his health deteriorates.

[17] BioWare started with a written description of Thane, and wanted to emphasise him as a "career assassin" while keeping him attractive as a possible romantic interest for female players.

He joins Shepard on a pro bono basis following his successful assassination of Dantius, stating that he has nothing left to lose, and he hopes to right many wrongs he has found in the galaxy before his death.

Kolyat's contracted target is a racist turian politician who extorts human rackets while promising to reduce crime in the Citadel Wards.

[25] Tom Marks remarked the internal conflict present in Thane makes him compelling as a sidekick, calling him the "personification of Shepard’s own Paragon and Renegade choices, and is the literal representation of their team marching slowly toward almost certain death".

[27] Tina Amini from Kotaku claimed that she reloaded an earlier save and spent at least another 40 hours making alternate decisions for her Mass Effect 2 playthrough just to ensure that Thane, whom she find compelling as a love interest for her Shepard character, survives the suicide mission and expressed a hope that their romance story arc would be continued for Mass Effect 3.

[28] Phil Savage from PC Gamer remarked that Thane's ending in Mass Effect 3 is brilliant, calling it a "quiet, sad triumph"; he's surrounded by family and friends at his deathbed, content with what he's achieved.

He likes that BioWare still made an effort to remind players to cherish the things that matter to them as individuals, such as their life goals and loved ones, even if Mass Effect is a game series that resolves around big, galaxy-shifting decisions and impossible odds.

[29] Scott Deakin, writing for GamesBeat, found his opportunity to avenge Thane, a character he was emotionally invested in, by finishing off Kai Leng during a cutscene to be deeply satisfying and cathartic.

[31] The comparison between Kepral's Syndrome and cystic fibrosis provided by Weekes resonated with Elizabeth Rogers from The AbleGamers Foundation, who explained in her article "The Problems and Joys of Thane from Mass Effect" that she suffers from the same condition: a life-threatening genetic disorder that fills her lungs and pancreas with mucus, and that like Thane, her lungs will inevitably no longer work.

She expressed a view that another writer who identifies as being chronically ill would probably have created a space for Thane to exist without death, "to be disabled and kicking ass well into the end of the series", but is content that he represents a movements towards greater inclusivity and representation of minorities in a video game.

He observed that Mass Effect 2 does not portray its religious and spiritual themes in a positive light, but he considered Thane to be an interesting case because the violence he commits is not informed by his religion, "although it allows for it.

"[12] GamesRadar's Jordan Baughman cited Thane as an example of BioWare's "The Honor-bound Psychotic" character archetype, specifically a religious zealot who "adheres to a special code that dictates his murder frenzies".

They contrasted Thane's positive reception as an unambiguously pious character to the broad negativity many players have shown towards human squadmate Ashley William's expressions of faith in the original Mass Effect.