You can try completing certain quests or participating in specific events related to it. Sometimes, rare drops from monsters might also give you a chance to obtain it.
One good order could be starting with the Tutorial Island quests as they introduce the basic mechanics. Then move on to the Lumbridge quests which are relatively easy and build a foundation. After that, quests like the Vampire Slayer quest can be a good next step as it has an interesting story and unlocks some useful items and areas.
For a new player, start with the basic beginner quests like the Imp Catcher. It's easy and gives a feel for how quests work. Then, try the Witch's Potion quest which is also simple but starts to introduce more of the game's world. After that, the Dragon Slayer quest is a big step, but it has a great story and is a classic in the OSRS quest line.
The following are some novel recommendations similar to the Devil Lord: " Coming Against the Wind in Exchange for Your Glory "," Koi Milk Bun is Three and a Half Years Old, Six Older Brothers Fight for Favor "," Group Favor Fuwa: Little Milk Bun Is Milk and Fierce "," Love at First Sight: A Dainty Wife, Too Black-bellied "," All-rounded Spiritual Master: Black-bellied Devil Lord's Enchanting Concubine "," I Heard that the Devil Lord is Chasing Her Husband "," Forced to Be a Good Pet, Being Gently Coaxed by a Crazy Big Boss "," Sister Wild King's Show: The Mage Comes to Get Blue, Book of Troubled Times, Spirit Realm Walker, Tang People's Table, King of Imperial Beasts, Cold and Cold Demon Lord is too black-bellied, and so on. These novels might satisfy his interest in the subject matter of the venomous demon.
The following are some novels that are similar to the Black Demon Spirit: " National Spirit Control: Super Evolution at the Beginning "," Demon Spirit Era "," Qing Ben Demon Spirit "," Global Demon Transformation "," Demon Spirit Tide "," The Peerless Demon Spirit of the Tang Sect "," My Strongest Demon Pet "," Mountain Sea Demon Control Record "," Demon Spirit Record "," The Battle of Gods Cultivation Demon Chapter ", etc. These novels involve the story of demon spirits and may be of interest to you.
I'm not sure exactly which specific 'Black Coach Black Demon stories' you are referring to. There could be various fictional or cultural tales that might involve such elements. It could be part of some local folklore or a very specific genre of horror stories.
Another theme might be the supernatural crossing over into the normal world. The black coach, which is often a symbol of the otherworldly, and the demon inside it break through the boundaries of our reality. This can represent the unknown and uncontrollable forces that can disrupt our lives. It also often has elements of mystery, as the origins and purposes of the coach and the demon are usually left to the imagination or revealed slowly in the story.
In some fictional tales, the black coach might be a magical vehicle. The white wife could be a character who is lured by the black demon. For example, the black demon might use the allure of the black coach to draw the white wife into its dark world, and then she has to face different challenges to escape.