The correct answers are: Come what may, I shall defeat this dragon before dinnertime! Far be it from me to tell a fire-breathing reptile how to behave, but it really shouldn't burn down villages. Suffice it to say, my armor is completely fireproof.

English retains the subjunctive mood in several fossilized, fixed expressions.

"Come what may" means "no matter what happens." The verb come is in the base subjunctive form.

"Far be it from me" is a polite (or sarcastic) way to introduce a criticism, using the subjunctive be.

"Suffice it to say" means "it is enough to say," using the subjunctive suffice.

Changing these verbs to indicative forms (like comes or is) makes the idioms grammatically incorrect!