The Blood Fiend's superior regeneration wasn't the only thing that made it better than the Flesh Golem. Unlike the Flesh Golem, who could only use its physical body to attack and defend, the Blood Fiend could use magic. It was a rudimentary usage where it just extended its arm with swords and blades of hardened blood. Those attacks weren't as easy to defend against or block, and it happened on several occasions that the Flesh Golem lost its arms or legs.
The Blood Fiend also started using shields of blood to block Toz's Fireballs, even if it didn't look like they did much damage to the Blood Fiend.
But the most annoying piece of magic that the Blood Fiend started using was the blood pool it spread out beneath itself. The Blood Fiend naturally didn't have any trouble moving around, but the sticky blood held onto Kahlia's and the other's legs. If they had been any weaker, they wouldn't have even been able to resist getting pulled down into the swamp of blood.
