"Even with the volatile nature of human growth around his age taken into consideration, this Sinner seems to get particularly startled or frown when spoken to. He isn't used to real combat at the moment, meaning that he may struggle to keep himself together at the sight of something as mild as spilt innards at first. As there may be those with violent tendencies among your crew, we recommend taking an approach focused on positive reinforcement with this Sinner. He appears to possess a murderous gaze that he himself isn't aware of; this is a hopeful sign that he has the potential to grow into an expert of our company's profession with the right stimuli." Return home?
The Limbus Company Wiki describes Sinclair as 'an anxious and self-conscious man with a blatantly empathetic nature.' His particulars are listed as "wishy-washy", "overdependent", and "inexorably insecure". Sinclair is frequently likened as an egg that is yet to hatch, due to growing up sheltered in the prosthetic-loving town of Calw, and he shows an innocence and naivete not found in the other sinners, despite his ability to kill. Though, it has taken him a while to get used to this part of his job, after his Canto and onwards, he grows more used to the violence of the City, which he has more complex feelings about.
Sinclair is also depicted as separated between two worlds: the light and innocence of his home life, and the darkness shown to him by his classmate, Kromer. As much as he loved his family, he was discomforted by their transformation with full-body prosthesis, which was taken advantage of by Kromer, leading to his entire family being killed by her on Christmas Eve. He's shown to have an intense hatred for her as a result, confessing a desire to crush her skull during battle in the Observation Logs.
Most interestingly, Sinclair is a deeply empathetic man. He acts as the interpreter of Ryoshu's SANGRIA, and translates her abbreviations with decent accuracy, and also frequently wonders about the lives and emotionals of abnormalities in Observation Logs. Despite his trauma and mental turmoil, he still has much care and sympathy in his heart for those around him, and makes use of it whenever he can, frequently lending kindness and understanding to his fellow sinners.
I've been attracted to Sinclair ever since I started playing. The 'sweet boy with a dark side' trope has always been very intruiging to me, and I think he exemplifies this trope in an entertaining and alluring way. Not only is he my boyfriend, but I've written Vien (next to Sinclair in the fan art) to be with him in the Limbus Universe, as my real self cannot yet reach him. He is my lovely pathetic German boy, and I know he loves me back. Sinclair, I know all the fanfiction I write of us would shake you to my core. Know that it would all become real if you could sit beside me. I love you.