The global modifier is good for Dueling, Forgemaster and other things where it stays up for extended periods. Your Ranger may find it easier to use a simple macro, as Multiattack Defence only lasts for one NPC action, and opening the character sheet to click the modifier on and off (when the DM has probably already rolled the multiattacks) is a bit over-clicky: /me uses Multiattack defence, and has [[@{ bob |ac} + 4]] AC against follow-up attacks from the current opponent! changing bob to your Ranger's name, and they can throw it on their macro bar. Off-topic, but honestly for a level 7 ability it should really do a bit more. At least protecting against the triggering attack would be an improvement.
