The 27th volume of Negima was probably the strongest one yet & that's because it's mostly just Rakan vs. Negi. Rakan vs. Negi is perhaps the best fight of the series (though I don't think there's a ton of options honestly, Takamichi vs. Negi was the gold standard before). The final play where Negi "won" was definitely the highlight of the fight. I also enjoyed the development Tosaka got. This chapter itself, ended with a standard but promising discussion. It's taken forever but we should be moving back towards the Fate story-arc & we know he was watching the match so with that knowledge I don't think Negi will be able to straight up annihilate him, at least I hope not. Maybe the darkness will be more of an issue towards taking down Fate than Fate himself, considering how powerful Negi's gotten.