This is a homebrew item for 5th edition Dungeons and Dragons. Modeled after the Staff of Power, it exists to represent the idea of a caster gaining a degree of mastery over natural elements.
Staff of the Elemental Master
Staff, Very Rare (Requires attunement by a Druid)
This 5’ staff is made of the gnarled, petrified branch of an ancient redwood. It weighs over 240 pounds; however, once attuned, it becomes as light as fresh cut timber and can be used as a magic quarterstaff in Melee.
A Druid attuned to the staff can always draw breath in any environment, and gains resistance to fire and lightning damage.
The staff has 20 charges, and regains 1d8+2 charges every sunrise and sunset. The staff can regain an additional d6 charges per day by submerging it in a large quantity of any natural element that is highly active (e.g. a raging river, a burning conflagration, a gale-force wind, etc). If you expend the last charge, roll a d20. On a 1, the staff retains its ability to grant breath in any environment, and damage resistances, but loses all other abilities. On a 20, it unleashes a level 9 lightning bolt directed by the wielder, using normal spellcasting rules.
Lightning Strike: When you hit with a melee attack using the staff, you can expend 1 charge to deal an extra 1d6 lightning damage to the target.
Spells: While holding the staff, you can use an action to expend 1 or more of its charges to cast one of the following spells from it, using your spell save DC and spell attack bonus: Gust of Wind (2 charges) Plant Growth (3 charges); Move Earth (6 charges); Lightning Bolt, 5th level version (5 charges); Wall of Fire (4 charges); Control Water (4 charges); Control Weather (8 charges)