She ignores it when she first sees it, the flash of silver out of the corner of her right eye. There's far too much going on right now to be sure that she saw anything. But she sees the flash again and again, in different eyelines, demolishing rows and rows of Thanos' troops. When the flash stops, her world slows down around her. It was him, still in the bloodstained, bullet hole riddled uniform from years ago.
She was seeing things. She had to be. A side effect of coming back to life, or some witchcraft used by Thanos to distract her. She let out a roar as she lunged towards the figure of her brother, fists raised with red magic swirling around each of them. The figure turned towards her with open arms and a small smile on it's face. Her right fist made contact with his jaw and he fell a few steps backwards. Wanda generated a concussive blast of magic to disable the troops gathered around the two of them. The figure of her brother grasped his jaw with one hand while reaching out towards Wanda with his other.
"It's me, Wanda." He whispered. "It's Pietro."
"My brother is dead." She replied, monotonously. She generated another wave of magic but the silver flash disappeared before she could destroy the hallucination or magic that was causing her to see her brother.
It wasn't until hours later, when the fighting was over and the world was at peace again- she saw him, really saw him. He was standing on the periphery of the crowd of heroes, new scrapes and gashes adorning his skin. He was kneeling on the ground, clutching at one such gash in his skin. Wanda blinked.
"Can you see him too?" She asked to the person next to her. Steve followed her gaze and nodded.
"I saw him during the battle. He did good." Steve smiled down at her.
Wanda approached the kneeling person slowly, as if tentative and afraid. Her brother's silver blue eyes met her own and she gasped, falling to her knees in front of him.
"Is it really you?" She asked, placing a hand on his cheek, as if checking if he were solid.
"Yes." He replied, cautious as hew still sported a bruise on his cheek where her fist had made contact. "Please believe me."
She mulled over possible replies in her head before just uttering: "I love you."
Pietro surged forward and captured her lips with his in a searing, long awaited, kiss.
"I love you, too." He smiled after pulling away. Wanda's muscles simply gave out and she tumbled into her brother's arms.