Kaeldur lost one of his arms in a clash with the Undying.
At first, it didn't look like the Undying would be capable enough to cause actual harm to the Devils, let alone Nial because each of them was at the Deux rank, while the Undying was only at the third Tier.
At the third Tier, an Ascender was roughly as strong as an Original at the Prometheus rank, or so it was supposed to be. However, the Undying turned the tables and was giving not one, but three of his opponents a tough time with the use of the unique God rank techniques he had learned to utilize.
One of the techniques was the 72 Slashes of Destruction Sword Style which was utilized with Dilan's sword. The Undying shrouded the sword in a membrane that was created with the Power of Destruction, and an Aura called Immortality Aura.