Shouldest take (arēis). First aorist active subjunctive of airō (liquid verb).
From the evil one (ek tou ponērou). Ablative case with ek, but can mean the evil man, Satan, or the evil deed. See same ambiguity in Mat 6:13. But in 1Jo 5:18 ho ponēros is masculine (the evil one). Cf. Rev 3:10.