Istar arc. Later she began to gradually lose her memories about the Seven Deadly Sins, because of Gowther's powers, Lost World. As she finally forgot about the whole time spent with her comrades, she leaves Camelot to come back to her hometown, Megadozer.
Yes in season 3 when king and Diane meet with drill and gloxina in the cave. She gets all her memories back. Yes, Diane remembers King. In Season 4 when King and Diane are training, they encounter Gowther who restores Diane's memories.
After his battle with Diane, Gowther erases Diane's memory of the Seven Deadly Sins with "Lost World" in order to disprove Diane's statement that memories and feelings cannot be erased.
The episode didn't do much to explain why Diane's memories were stripped, but readers of the manga know all about her amnesia. Audiences may assume Galand's attack prompted Diane to lose her memories, but it is actually the fault of Gowther. The fellow Sin used his Lost World power on Diane to make her forget King.
Sin of LustGowther. Gowther is a member of the Deadly Sins who bears the Sin of Lust, symbolized by the Goat symbol tattooed above his breast, he is an androgynous and bespectacled bookworm with pink hair who originally clad himself in a massive suit of armor Merlin designed to stabilize his power due to his unstable mind.
Gowther erased Diane's memories using Lost World. When she regained her memories and returned to the other sins, Gowther began regaining his own. When he tried to use Lost World on himself out of fear for the new feelings, Diane stopped him and encouraged him to let them come.
Hawk Mama was strong enough to send Twigo and the Beard of the Mountain Cat knights flying when she revealed herself, as well as charge through and kill an entire group of red and grey demons by herself with what seemed like little effort.
Superhuman Strength: Doomsday is able to easily lift in excess of 100 tons ,Doomsday possesses vast super strength, even more than Superman.
Meliodas is more powerful than escanor. Escanors powers are the powers of an arc angel named mael, and meliodas powers are that of the demon king along with his own. So meliodas has full control over his powers, and escanor using a borrowed power has very little control.