That was, in fact, Gryphon, in Hopelessly Lost 3.

"The thermal sights were Gryphon's own idea; a small heating
element in the front blade and one small chillchip on each side of the
rear sight. When he was "seeing" thermographically, the dots would be
lined up in a straight line, blue-yellow-blue, when he was on target."

...!
Stoke Mandeville, Esq & The Victorian Ballsmiths
"Nobody Want Verdigris-Covered Balls!"