Reading the etymology of fiend propelled me to read Univ. Texas's page on the PIE etymon pē(i)-, pī- 'to hurt, scold, shame', whose Semantic Fields are stated as:
to Harm, Injure, Damage; Shame (n).
Under this PIE etymon, I saw the Latin adverb paene listed; but per Wiktionary, it does not connote or denote any negativity or injure or shame. So why was paene assigned to this PIE etymon?