At the end of King Killer, once you have defeated Ivarr and returned to Ubba in his tent, you will need to inform Ubba about how his brother died. Here you will have three dialogue choices, but the consequences of each will differ depending on whether or not you gave Ivarr his axe. See Send Ivarr to Valhalla or Deny Ivarr Valhalla? for the consequences of this choice.

If you gave Ivarr his axe¶

• Ivarr died badly: In a later quest, Ubba will be angry that you lied to him
• Ivarr died well: In a later quest, Ubba will be grateful that you were honest with him
• Ivarr wanted death: Ubba will be grateful, as this option results in Eivor telling Ubba that Ivarr wanted to be sent to Valhalla, and Eivor sent him there

If you refused Ivarr his axe¶

• Ivarr died badly: In a later quest, Ubba will be grateful that you were honest with him
• Ivarr died well: In a later quest, Ubba will be angry that you lied to him
• Ivarr wanted death: Ubba will be angry, as this option results in Eivor telling Ubba that Ivarr wanted to be sent to Valhalla, and Eivor sent him there (which in the context of Eivor not giving Ivarr his axe, is a lie)