Genshin Impact 4.0 update has added five new craftable weapons, and to get them, you need to get their blueprints. These blueprints can be purchased in exchange for some materials that you can find by exploring Fontaine. One of them is the Pluie Lotus that you require to purchase Rightful Reward (Polearm).
As per the description, Pluie Lotus is, "A plant that grows in environments rich with Hydro. This plant can be found everywhere in Fontaine after its long rainy seasons. The plant is named "Pluie" - which means "rain" in the local tongue - for that reason." Now, it will be a difficult task to explore a massive region like Fontaine to farm Pluie Lotus, and thus, here are their exact locations to save you a lot of time.
Genshin Impact: Pluie Lotus Farming Location
As the in-game description suggests, Pluie Lotus can be found in a Hydro rich environment, which means you can find them near lakes and river banks in Fontaine. However, the exact locations of all of them are still unknown, but we will update this page once we have details about it.
You will need a total of 10 Pluie Lotus, 10 Bulle Fruit, and 10 Condessence Crystals in order to get the Rightful Reward (Polearm) weapon blueprint. Once you have all of these materials, talk to Estelle, Fontaine's Blacksmith, and talk to her. Give her the materials, and she will craft Rightful Reward (Polearm) weapon for you.
While exploring, you can travel fast from one location to another by using Teleport Waypoints and the Statue of Seven to collect them quickly. In addition to this, make sure that your HP is enough to fight enemies, as you might encounter some while exploring.