what happensn when a star dies in the battle with the black thing? why is the danger greatest for Charles Wallace?

In the novel A Wrinkle in Time, a
star battles the Black Thing and partially obliterates the darkness. However, in doing
so, the star dies. Charles Wallace, who has the gift of being able to enter people's
minds, attempts to also obliterate the Black Thing by going into its mind to understand
it. In doing so, however, Charles loses his sense of self and becomes trapped, almost
completely under the control of the Black Thing. It was his perceptive gift of being
able to completely read other people's minds that made him the most
vulnerable.