He left biting his fingers in anger. = We use the -ing clause when two things happen at the same time. 'He left the room biting his fingers in anger.' 'She's in the kitchen making coffee.' 'I'm online browsing some sites.'

Hi Rrooxx! "He went (=he left?), biting his fingers in anger." The second clause is descriptive, so I don't think it needs the full-sentence treatment. "Bite"->"biting". This keeps the long vowel; "bitting" indicates a short vowel... and isn't a recognised word anyway. ;) If anger causes you to act a certain way, it's done "in anger".