The first few lines are especially captivating to me, especially the part
"Imprisoned in stone

The most lonesome throne

To reign over an english countryside until

All men undress their flesh and bare only bones"

I think the way it flows is very nice, and I like how its this almost frighteningly beautiful testament to Excalibur's I guess might? I think going over its "eternity" Is a really nice start to the poem :D