Answer:
I start with T end with T and within me is T.
A single syllable do I claim black was my most famous name; Fetal to mortals here below thousands have I slain in a single blow.
I am a seed with three letters in my name. Take away the last two and I still sound the same. What am I?
It rows quickly with four oars but never comes out from under its own roof. What is it?
My first is second in line; I send shivers up your spine; not quite shining bright I glitter in the light.
It's what light turns into in the night