Ichigo is a special Shinigami that own the ability of hollow, so he can use the power of hollow mask to fight. But up to now, Kubo in the Bleach
episodes never told us the true energy of Ichigo's hollow power, he used to beat Urukiora by the totally hollow body, but he lose his mind. So we cannot judge the really power by this
At the Fullbring episodes, Ginjou said that the man's mother who used to attacked by hollow whenthere are still Pregnat, so the baby can saw hollows even can use the ability of hollow, this is the original style of Fullbrings. In this last Bleach episode, Neliel even go outside of the Hueco Mundo and ask help from Ichigo. After enter the Hueco Mundo, I believe Ichigo will find the truly secret of his Hollow power and right way he will go on. And this time, Shinigami and Hollow have an same enemy! Looking forword to see the combine of those guys!
When the empire into the Hueco Mundo, he just want to choice some strong fighters. So I am afraid that he will beat Ichigo at first, because we know that he can limit the Bankai. Horrible ability. It's a huge crisis to Soul Society!