The companion system really shines once you understand the timing of their abilities. For atreus, you'll want to watch his instinct tree carefully, especially that watchful protector skill which makes enemies focus on him instead of you - perfect for when you need a breather during tough fights. His archery skills become crucial when dealing with shielded enemies, since his sonic arrows can stagger them right as they're about to attack. The aggression tree unlocks later on but adds some nasty close-range options that combo well with your own attacks.

Freya's a bit different, and timing her vanir magic is absolutely essential. Those vine attacks need about 2 seconds to properly root enemies, so trigger them when you see groups bunching up together. Her valkyrie form becomes available after specific story beats in vanaheim, and you'll want to activate it right before heavy combat sequences since it has a cooldown. The real trick is watching for enemy telegraph animations, then commanding either companion with square exactly when you need crowd control or specific elemental effects.

Good to know - both companions get more aggressive with their abilities the more you invest in their skill trees, but they won't use certain moves until you've completed specific realm storylines. Their positioning ai also adapts based on which skills you've unlocked, so you'll notice them naturally finding better angles for their attacks especially during boss encounters.