Info Scarlet Witch:
The Scarlet Witch (Wanda Maximoff) is a fictional character that appears in publications published by Marvel Comics. The character first appears in X-Men #4 (March 1964) and was created by Stan Lee and Jack Kirby.

Initially, the Scarlet Witch had the mutant ability to manipulate probability via "hexes". Visually, these hexes could manifest as "hex spheres" or "hex bolts" and increased the probability of various unlikely phenomena, including spontaneous combustion of inflammable objects, rapid rust or decay of organic or inorganic materials, deflection of objects and powers in flight, and disruption of energy transmissions or fields. These hexes were relatively short range and limited to line of sight. Casting a hex requires a gesture and concentration on her part, though the gestures are largely a focus for the concentration. Despite this precision, the hexes are not necessarily guaranteed to work, particularly if Wanda is tired or using her powers excessively. If overextended, Wanda's hexes can backfire, causing probability to work against her wishes or to undo previous hexes. The effects are varied but almost always detrimental to opponents, such as causing the artifact the Evil Eye to work against inter-dimensional warlord Dormammu, the robot Ultron to short circuit, or a gas main underneath the Brotherhood of Mutants to explode. Wanda is an expert combatant having been trained by both Captain America and Hawkeye, as well as being an adept tactician due to her years of experience working as an Avenger and her experience in a variety of combat situations.

Writer Kurt Busiek redefined the Scarlet Witch's powers, and maintained that it was in fact an ability to manipulate chaos magic, activated when she was born. Busiek's redefinition upgraded Wanda's powers substantially, and she is shown as being capable of feats such as the resurrection of Wonder Man. She was here described as the "nexus being" of the Marvel Universe, capable of birthing children with power enough to challenge avatars of Eternity.

Writer Brian Michael Bendis revamped Wanda's powers yet again, with Doctor Strange stating that there was in fact no such thing as chaos magic, and that Wanda had been altering reality all along. Her power was here depicted as sufficient to rewrite her entire universe, and cause multiverse-threatening ripples.
Source: wikipedia.org