The Persons referenced at "who worship" (plural verb) represent the heavenly worshipers i.e. 24 Elders, Four Living Creatures, 'A Martyr', and 'An angel'; but this is not the context of verses 1 and 2. It would be more correct to tag as "A Person" or "Person in Revelation", irrespective of how the earthly "temple of God" is interpreted.
