The second part of Stoic Endurance helps your tanks and larger constructs keep kicking even after heavy damage. Enemies will need to chip 17 wounds off of an Iyanden Wraithknight before seeing any appreciable difference in its combat effectiveness!
It’d hardly be an Iyanden army without some ghost warriors, would it? Wraithblades in the new codex are just as deadly as they’ve always been, with some added bonuses. Smaller Wraith units have received an additional point of Toughness in the new codex, bringing Wraithguard and Wraithblades up to Toughness 6 and Wraithlords to Toughness 8, making them markedly more resilient against incoming enemy fire.