All friendly Nurgling units (see Daemons of Chaos) within 12" of Morbidex Twiceborn have the Regeneration (4+) special rule
BackSource: Warhammer Armies Project: Unofficial 9th Edition (v2.2)
All friendly Nurgling units (see Daemons of Chaos) within 12" of Morbidex Twiceborn have the Regeneration (4+) special rule