OOC:
Step one is to examine the souls to determine their worth, as you are at a bonfire this happens for free...
Fading Soul. The fading soul of a lost Undead who has gone Hollow. Offer at a bonfire to gain 100xp or for trading. The soul is the source of all life, and even in undeath, or hollowing, the mind seeks souls.
Almian Legionnaire Soul. These soldiers from a distant land marched against the Firekeep at the command of those who would break the age of light. Offer at a bonfire to gain 150xp or for trading.
Legrion Tortoise Knight. The king of the Firekeep clad his strongest warriors in heavy plate and equiped them with weapons no normal man could carry. Their lack of manuverability was the inevitable end to these iron juggernauts. Offer at a bonfire to gain 1400xp or use for trading.
Legrion Lancer Soul. The front line troops that once defended the Firekeep from all it's foes. Nimble and equipped with a powerful spear they serve the King of Fire even in death. Offer at a bonfire to gain 200xp or use for trading.
Soul of Mahjim the Gate Warden. This warrior came to Legrion on a long pilgrimage from a far off land, and swore fealty to the Fire King. He stands watch over the gates of Fire Keep and deny entry to all who would violate the sanctity of the Throne of Fire. Offer at a bonfire to gain 2200xp, use for trading or to create a powerful item.
OOC:
Now that you are at a bonfire you can destroy any number of these souls you like to convert them into xp and add them to the XP total like you normally would. In case it would change your mind about what to do with the boss soul, it will never be dropped on your death, with lesser souls being dropped preferentially.