Rivendell have skilled Cavalry and Infantry.
Unlike the Lorien, Rivendell have fewer archer units but have more heroes 4 of which can fight on horseback.
One of their greatest strength comes from their Elven Lightbearer which when fully upgraded is stronger then some heroes they have the powerful Searing Light spell.
Lightbearers are expensive to upgrade and only 5 can be built at any one time.