Learn Spanish (Latin America): Compré un talismán para ahuyentar el peligro.

We use para + the infinitive (ahuyentar) because the subject of both actions is the same: I bought the talisman, and I am the one warding off danger. You only use para que + the subjunctive to express a desired outcome when there is a change of subject (for example, Compré un talismán para que ahuyentes el peligro - I bought a talisman so that you could ward off danger).

What is the verb "ahuyentar" related to, and how else can it be used?

Ahuyentar means "to scare away," "to ward off," or "to banish." It comes from the same root as the verb huir (to flee) — so it essentially means "to cause to flee." You can use it for abstract concepts like el peligro (danger) or la mala suerte (bad luck), as well as physical things, like chasing away stray dogs, birds, or mosquitoes.

Why does "talismán" have a written accent mark, and does the plural form keep it?

It has an accent mark because words ending in -n, -s, or a vowel naturally stress the second-to-last syllable. To force the spoken stress onto the final syllable, it needs the written accent. However, in the plural form (talismanes), an extra syllable is added. The stress then naturally lands on the second-to-last syllable (-ma-), so the written accent mark is dropped.

Why do we say "el peligro" here instead of just "peligro" like we do in English?