He's tall, unemotional, quite intimidating, and a high-ranking member of the spirit Lethe's gardeners, a group of primarily chimera (with the odd soul here and there) who hunt down newly spawned chimera and introduce them to the "wonderful" Altered Lands. Due to being tall,unemotional ,and quite intimidating, Gabriel tends to scare off most young chimera--not that he cares, he doesn't hunt for chimera anymore; he's more interested in hanging around Lethe and tending to the gardens around Lethe's domain. He's quite sweet underneath his intimidating exterior, and means no harm to anyone, most of the time. Gabriel's known Lethe for quite some time, as they met due to Gabriel being curious about the process of death and how beings that live in the Altered Lands die, as before he was a gardener, he was a weapon maker, using plants he would grow and create to make weapons or "conveniently" kill people. Poison? Weird non-standard weapons? Causing poor suckers to conveniently die from (the nonexistent) "Hanahaki Disease"? Just ask Gabe, and he'll give you everything you need, and more!

Gabriel's also convinced himself that everything good that has happened to him is completely undeserved believing that he's to blame for his family splitting apart, for chimera like him being hunted down, for everything bad that has every happened to him and his loved ones. And so, he refuses to use his abiity, his supressed emotions causing him to develop a condition where the pent-up energy he has manifests as flowers that grow and feed off of all that energy, causing him to have awful headaches and fainting spells.
The cane usage is unrelated to this, he's always had an hard time walking.