It's not Love Trio, and not Buddy to be exactly, but something on the line of friends, very close friends.

Is not

Because its the correct translation

he used to live on earth and reincarnated as a baby prince davey, after the murdering of his mother, he got shoot with a bow and arrows by his half brother, and entered in a deep coma while his soul got to the hero's hall

*bo***

She's not, she act this way with the two only friends she ever made, and they're girls, if she really is, she would ask them to be her woman, but she never did, she's just that type of character that various animes has of girls harassing beautiful girls, just because they're beautiful or have great body or boots.

His body have infinite vitality.

The translation team changed, but he is a Calamity Dragon

In the anime the spear is explained, it's is a replica of a Sacred Treasure that consumes life-force to use and would kill it's user (the healthiest Human to ever exist don't die to it) and G** gave to him and his daughter the Farm Goddess is furious, because he gave the two to a human (The Spear and The A.M.F.T).