So the Nightsong encounter is one of those key decision moments where timing and positioning really matter. When you reach her chamber in the Shadow-Cursed Lands, notice her initial stance - if you're planning to fight make sure your squad is spread out to avoid her AoE shadow attacks. For those aiming to spare her, position Shadowheart front and center since their dialogue triggers unique interactions.

During combat she telegraphs her major attacks with a distinct shadow aura buildup, dodge the moment you see the darkness peak. Her recovery window after the shadow burst gives you about 3 seconds for counter-attacks, but maintain medium range since she can still cast quick spells. At 50% health she adds a phase-shift ability that lets her blink to shadows around the room, counter this by keeping your team near light sources which limits her movement options.

The real strategic depth comes from the consequences though. Killing her triggers the Dark Justiciar path - Shadowheart gains new abilities but Last Light Inn gets destroyed, and the shadow curse intensifies across the region. Important timing detail: you need to decide before reaching Act 3 since this affects multiple quest chains. Sparing her opens up the redemption route, unlocking Selûne's artifacts and ally support, plus Nightsong becomes available for the Ketheric fight where her shadow manipulation abilities really shine against his defenses.

Keep in mind your companion positioning during the key dialogue moments, since their approval changes based on your choice and affects later story beats. The window for each decision path closes permanently once made, so consider the combat and narrative implications carefully.