Quiet! Put up with a little headache. My magic power is completely depleted. And it's all the princess's fault.
Literal
Noisy is-[emphatic-なっ]! Little [gen-の] headache [about-くらい] endure. I [topic-は] magic-power [subject-が] completely-empty is. That [and-も] this [and-も] princess [gen-の] fault is-[ぞ].
A dramatic fantasy-fiction speech. 余 is the archaic imperial/aristocratic first-person pronoun — 'I' as used by royalty or ancient emperors. すっからかん is a casual/colloquial intensified form of 空 ('empty'), meaning 'completely empty, bone-dry.' 魔力 ('magical power / mana') is genre-specific. それもこれも ('both this and that, all of it') is a fixed expression blaming everything on one cause. 姫 ('princess') matches the archaic speech register. Typical 'fantasy demon lord' dialogue.