Knights of the Zodiac (Saint Seiya), Vol. 2 — Masami Kurumada

The Galaxy Tournament rages on as Unicorn Knight Jab takes on the ferocious Lionet Knight Ban in a brutally decisive battle. Meanwhile, in the frozen wasteland of Siberia, Hyôga the Swan Knight shatters the thick ice to swim to visit his mother's lonely grave in the frigid waters. He receives a strange letter from Sanctuary commanding him to kill his fellow Knights of the Zodiac for betraying their oath--to never use their powers for personal gain. He returns and witnesses a bloody match between Pegasus Knight Seiya and Dragon Knight Shiryû. After watching them risk it all and nearly die in the process, Hyôga begins to realize that maybe these Knights are fighting for something more than just personal gain!