As to your question about ἂν, JM, just remember that ἂν always goes with a verb (here διαφθαρείη), never with an adverb or adjective. ὅπως ἂν διαφθαρείη = "in order that he might be destroyed."
Here are points to consider before translating this sentence:
1. καλούμενος is passive, not active.
2. The word for "plain" is πεδίον. Παιδίον is the diminutive of παῖς, so look it up under παῖς.
3. θεῖναι is the first aorist active infinitive of τίθημι, "put." Study its conjugation on p. 278.
Give it another try!