In most cases, their mating is a result of a combination of factors. Maybe it's a deep emotional connection that develops over time, or a dramatic event that makes them realize their feelings for each other. It really depends on how the fanfiction writer decides to shape the story.
You can try fanfiction websites like Archive of Our Own (AO3). It has a large collection of fanfictions from various fandoms, and you're likely to find some great Bella and Howl Pendragon mate fanfictions there.
One popular Bella and Howl Pendragon mate fanfiction might be 'The Bond of Bella and Howl'. It often explores their relationship development in a magical world. It could show how they meet, overcome challenges together, and how their bond as mates strengthens over time.
There are various reasons. Maybe he underestimated a foe's strength, or a spell backfired on him. Another possibility is that he took a risk for a greater cause and ended up getting hurt.
Saber from Fate/Stay Night would be an obvious choice. Since she is also related to the Arthurian legend, there could be a lot of interesting interactions between them. They could compare their experiences as king, or even fight side by side against a common enemy.
The Duke Pendragon in the novel is often portrayed as a strong and fearless leader. He is usually skilled in combat, which helps him defend his land and people.
It's about a series of adventures. It usually involves a hero's journey through different worlds, facing various challenges and foes. It's full of action and mystery.
Pendragon Visual Novel is often about the Arthurian legends. It might include the adventures of King Arthur, his knights, and the magical elements associated with that era. It can have various storylines that explore themes like chivalry, love, and power struggles.
The Howl novel is a captivating tale that follows the adventures of a protagonist in a fantastical world. It involves elements of magic, mystery, and self-discovery.