Khalid Bin Waleed was born as a soldier. He was brave and courageous. He was born in Quresh Family. He opposed Muhammad PBUH when He declared that He is the prophet of Allah. When the Holy Prophet Muhammad PBUH starting preaching of Islam Khalid Bin Waleed announced war against Muslim and he won that battles with his bravery and cleverness.
The Holy Prophet Muhammad PBUH send a messenger to him that and tell him that you are such a great warrior and also a intelligent general but I'm suspesious that why you oppose me . In reply Khalid Bin Waleed came to The Holy Prophet Muhammad PBUH and accepted Islam.
After accepting Islam he fought too many battles for Islam. He became the defender of Islam. He fought more than Hundred wars but never defeated by opposition. In the defens of Makkah He was appointed as a Leader of muslim Army by Prophet Muhammad PBUH to protect Makkah from Non Muslims.
Khalid Bin Waleed took a sword and stand to protect Kabbah. Allah says that Khalid Bin Waleed is the sword of Allah. No one can defeat him. He broke 10 swords to defeat three lac army of opposition with his only ten thousand army.
The history has been written that He was only conqueror who was undisputed and became Fatih of every single battle.