(1 update) Blade of the four seasons

This item appears to be a sword hilt. 

SUMMER - While grasping the hilt, you can take a Bonus Action to cause a blade of pure radiance to spring into existence or make the blade disappear. While the blade exists, this magic weapon functions as a Longsword with the Finesse property. If you are proficient with Longswords or Shortswords, you are proficient with the blade of the four seasons. You gain a +2 bonus to attack rolls and damage rolls made with this weapon, which deals Radiant damage instead of Slashing damage. When you hit an Undead with it, that target takes an extra 1d8 Radiant damage. Sunlight. The sword’s luminous blade emits Bright Light in a 15-foot radius and Dim Light for an additional 15 feet. The light is sunlight. While the blade persists, you can take a Magic action to expand or reduce its radius of Bright Light and Dim Light by 5 feet each, to a maximum of 30 feet each or a minimum of 10 feet each.

SPRING - While grasping the hilt, you can take a Bonus Action to cause a blade of sapping health to spring into existence or make the blade disappear.  When you attack a creature with this magic weapon they gain temporary hit points equal to 1/2 the damage delt. when you roll a 20 on the attack roll, you gain ((10+damage delt) multiplied by 2)  temporary hit points.

WINTER - While grasping the hilt, you can take a Bonus Action to cause a blade of ceaseless cold to spring into existence or make the blade disappear. When you hit with an attack roll using this magic weapon, the target takes an extra 1d6 Cold damage. In addition, while you hold the weapon, you have Resistance to Fire damage. In freezing temperatures, the weapon sheds Bright Light in a 10-foot radius and Dim Light for an additional 10 feet. When you activate the blade, you can extinguish all nonmagical flames within 30 feet of yourself. Once used, this property can’t be used again for 1 hour.

FALL -  While grasping the hilt, you can take a Bonus Action to cause a blade of amber dacay to spring into existence or make the blade disappear. Once per turn, when you hit a creature with an attack using this magic weapon, you can wound the target. At the start of each of the wounded creature's turns, it takes 1d4 necrotic damage for each time you've wounded it, and it can then make a DC 15 Constitution saving throw, ending the effect of all such wounds on itself on a success. Alternatively, the wounded creature, or a creature within 5 feet of it, can use an action to make a DC 15 Wisdom (Medicine) check, ending the effect of such wounds on it on a success.

Proficiency with a Scimitar allows you to add your proficiency bonus to the attack roll for any attack you make with it.

Notes: Bonus: Magic, Weapon Property: Finesse, Replace Damage Type: Radiant, Damage: Radiant, a creature (You get one power base on the season you attuned in for each time you attune for each season. (this weapon never takes more the one attunement slot.), Finesse, Light, Nick