Fantasy: I Evolved into a Giant Spider in the Universe

I was an orphan and had to join the Order, swearing to protect the people so they wouldn't have to suffer like I did. Eventually I succeeded and gained a new life at the cost of my life, but there was a catch. I was forced to transform into a spider, and I could only grow insignificantly in the early stage. Let's see how I can become a cosmic giant spider, one that can fill a continent in one mouthful. . . . . This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.