First of all, try not to post custom-coloured text. Blue against dark grey isn't very good for reading.
Next, you have a few grammar issues.
There was a Dragon, Abyssus, it was guarding the Jewel of Dragons. A thunder crackled in the sky, The Polynemus flashed violently in the sky.
The first sentence here is a run-on sentence. Basically, you're putting two sentences into the grammatical space of one without using conjunctions. You could do better to put this instead:
There was a Dragon, Abyssus, who was guarding the Jewel of Dragons.
The next sentence has what's called an uncountable noun. You don't have "a thunder" or "two thunders" - it's just "thunder". Unless, you mean one type of thunder, which seems unlikely. So it would just be "Thunder crackled in the sky."
It's also another run-on sentence, because you don't use conjunctions, again. The second sentence in that quote would be better phrased as:
Thunder crackled in the sky, and The Polynemus flashed violently in the sky.