Garo: Makai Senki Season 1

In the war against the nightmarish creatures known as Horrors, Mankind's most formidable line of defense has always been the power of the Makai Knights. But now, one by one, the Knights are being mystically marked for death by a mysterious magic user in a crimson mask.Even Kouga, the bearer of the golden GARO wolf armor, is among the afflicted, with the accursed mark slowly draining his strength, and making the use of his armor incredibly painful. Who is the Red Mask and how has he (or she) been able to target the Knights so effectively? All signs point to a betrayal from within their own ranks and now it's up to Kouga, Rei, and the other Knights to track down their enemy while they're still strong enough to defeat him!