Captain America leaves the Avengers because of these events, and the Black Knight eventually becomes the "de facto" field leader of the Avengers. During this time, he becomes romantically involved with his teammate Sersi (of the Eternals), but is also attracted by Crystal, one of the Inhumans' royal family. The Avengers are attacked numerous times by alternate versions of themselves, called the Gatherers, led by the mysterious Proctor. The relationship between The Black knight and Sersi soon come under strain, as Sersi proves increasingly unstable and more aggressive, so when the Avengers went to the planet Polemachus and the tyrant Anskar had killed an innocent girl, Sersi killed him immediately. Her fellow Eternals, led by Ikaris, pay a visit to the Avengers and tell them that Sersi was affected by the "Mahd W'yry", an incurable disease. In an attempt to stabilize her, and because she asked, Ikaris mentally bonds Sersi and Whitman with a process called the ""Gann Josin"", but this does little to slow the disease – not in the least due to Whitman's resentment at having the bond imposed upon him, and that he had come to the conclusion that it was Crystal he loved. With the bond, the Black Knight acquired more strength, red eyes, and an intimate mental connection with Sersi.