Reincarnated into a child - male protagonists

I LOVE THIS A LOT.

Main character dies after being killed and betrayed by his employer. He reincarnates into the youngest son of the company that got him killed.

Investments and business
Smart mc
No powers all tactic


Romance: yes, but not the focus

Large family
Battle of succession
Magic
Past memories

Romance: not so far

Battle of succession
Past memories
Magic
Spear user

Romance: I don’t think there is?

Doesn’t reincarnate
Child soldier
Poor background
Later turns into a teenager
No magic but like magic tools

Romance: no