They manage to do some damage!

As Grimmjow landed, he stalked towards them, his movements casual... like a predator who had already cornered his prey. "So, which of you is stronger?" he asked, and Rukia immediately turned to Ichigo.

"Ichigo, we need to fall back!" she shouted frantically, aware that this was not a fight they had a high chance of winning. Before she could make good on retreating herself though, Grimmjow dashed forward, and plunged his hand into her side. "Urk!" she grunted, trying to stay up, but ultimately collapsing. While being a genie made her essentially immortal, her body could still be destroyed, albeit temporarily. Of course, despite what she said earlier about that, Ichigo didn't have the details, so he didn't know she was in no real danger, so he rushed in to attack Grimmjow.

The Arrancar grinned madly as he blocked on his arm, his hard skin taking the blow from Zangetsu easily enough. Ichigo turned his head to Rukia, thinking fast. "Rukia, I wish you would heal up so we can pick up where we left off after this!" he shouted, not outright saying the sexual part, hoping alluding to it would suffice. He sure as hell wasn't telling Grimmjow about Rukia's nature, so made the wish as vague as he could.

"You'll have to live through today before you can do anything after it!" Grimmjow cackled as he kicked Ichigo away. Ichigo cursed as he skidded back, but got into a stance as he saw Rukia moving.

"Bankai!" Ichigo declared, and his cleaver changed into the black katana. He then began exchanging blows with Grimmjow, clearly on the back foot. Still, he was waiting patiently as Rukia got up behind Grimmjow, healed up.

Rukia smirked, pleased that Ichigo was already exploiting her powers intelligently. Even though she was never in danger of dying, this meant she could be of help against Grimmjow. "Second Dance, Hakuren!" she shouted from behind Grimmjow, who blinked and turned just in time to see the wave of ice coming at him. He was engulfed and frozen.

Ichigo, having had Grimmjow between himself and the ice wave, avoided being frozen and charged forward. "Getsuga Tensho!" he roared, but instead of sending out the attack in a large slash wave, he instead stabbed it forward, enhancing Tensa Zangetsu's edge. This condensed the Getsuga's power, and greatly enhanced the blade's piercing abilities. And he aimed right for Grimmjow's heart.

Unfortunately, Grimmjow was much stronger than D-Roy, and broke free from the ice in time to lurch aside, resulting in only his left shoulder being impaled instead. "Gah!" he cursed before punching Ichigo away, Tensa Zangetsu slipping right out of his flesh.

"Hado Number 4! Byakurai!" Rukia shouted, using the Hado in a similar manner as her brother, and shot Grimmjow in the back, directly between the shoulder blades. It burned through his jacket, and scorched his skin, but not much else, though it did make him snarl.