Basic Expert: Narcotics from Fantasy/RPG/Isekai Anime

Narcotics have appeared in fantasy Anime settings just as they have in real world Anime settings. Two recent examples include:

Divine Vine: this vine produces grape which when turned into wine addicts the recipient who drinks the wine compelling them to do anything for a drink. Anyone drinking the wine for the first time and failing a saving throw vs poison (adding/subtracting charisma adjustments) becomes chaotic while addicted. There is no magical cure.
Source: Is it wrong to try to pick up girls in a Dungeon 1&2)

Fairy Dust: this substance is bulk harvested from thousands of imprisoned faries by a crime syndicate. When consumed in quantity by non-magical entities such as humans the fairy dust turns them into wights under the control of any entity providing them with orders. It is fairy life force (Latena) so consumption affords no saving throw, though a fairy could sacrifice themselves to cure one person of dust contamination. Those regularly exposed detect of magic even after death. They leave traces through physical contact with surfaces, objects, and individuals.
The use of a specialized 'explosive' container that causes the fairy to go critical is described as the fairy dust equivalent of a tactical nuke with a five mile blast radius.
Source: Cop Craft

Bad Astronomy: finding historical parallels

Wanyudo, 1779

The funny thing about history is that is that eventually you find that others have made the same discovery in the past. Here we have the Yokai (mischevious spirit) known as Wanyudo that takes the form of a burning wheel with a grotesque central face.
Sure it could be some nasty battle Tactic where the face of some enemy is to cut off and stitched over the hub of a Cart or Wagon Wheel and set on fire as it is rolled down hill into a village to terrify the villagers during a violent raid, but it reminds me of a tiny Rubidium Star orbiting a distant White Dwarf and a wheel with spokes of debris falling back into the star - a star system lensing past Proxima Centauri. It makes you wonder about the origin of Yokai in general. What if they are Astronomical References?

The level of Technology required to make such observations would be very high. High enough that it would be the remnants of a civilization that either vanished in the distant past leaving only concepts and ideas for future generations, or a future civilization that will discover time travel.

So, in memory of the past, lets call this distant burning wagon wheel star system Wanyudo-1779.

Basic Expert: A Kick to the Groin

Very little consideration has been given to unarmed and unarmoured combat in the Basic and Expert Dungeons & Dragons system. Without Armour we know that movement rates are at twice that of an Armoured opponent meaning an unarmoured opponent could close the distance in a less than a single round. Likewise while surprise exists, it factors in to one's position in the combat turn cycle rather than any kind of bonus to the attack roll or damage.

Here we have a snipit from the Isekai titled Ixion Saga - Dimension Transfer in which the main character delivers a damaging blow to his opponent with a brutal kick to the groin. Apparently these ridiculous looking boots were the most expensive boots in the shoe store.

 Kick to the Groin                                                                                      
 Attack Location  Hit Roll       Type                      Recovery Time    
 Kick      Groin        Hit Roll        Stun                        3d6 Rounds           
                                 Critical Hit  +Organ Damage   Magic Heal Req.    

Dungeon Mastery: Being Tsundere should be seen as a kind of (Inter)national Epidemic

What is Tsundere?
Tsundere is a Japanese term for a character development process that describes a person who is initially cold before gradually showing a warmer, friendlier side over time. The word is derived from the terms tsun tsun, meaning to turn away in disgust or anger and dere dere meaning to become 'lovey dovey'. -Wikipedia

Its Relevance to Dungeons & Dragons
You will find that all Players and Dungeon Masters fall into this category. There is some damage that poisons humanity and those seeking refuge in Dungeons & Dragons seem hardest hit, perhaps because they are no more than a population sample. 
Dungeons & Dragons isnt just a game, its a shared experience where over time, players and Dungeon Masters grow just like their Characters and game-play Skills. Gygax and Co. have inadvertently staved off a significant spread of that epidemic with a globally accessible game that encouraged personal growth and human interaction. Beyond the game about killing people and taking their stuff it dragged kids out of their shells.
Where the Internet has given people the ability to hide in their room and communicate through a series of hostile acts escalating rapidly toward the failure of Civilization, Dungeons & Dragons was, oddly enough, the Panacea.

Basic Expert: Overusing Magic

Starting out an OP wizard...

Having caught an interesting anime called isekai wa smartphone (journey to another world with my smartphone) I noticed this little scene in the intro sequence and it reminded me of something from the cover of a Dragon Magazine (Issue #264).

I wont discuss the series other than saying his conversation with God over dying could have gone better. Yeah... that gets ugly.

Ending up an undead...

So imagine doing wizard stuff actually puts your spellcaster at risk. In the Anime world they use mana or life force to power magic, so burning through positive life force gets you to the negative plane pretty quickly.

So lets say your Magic-user/Elf spells memorized are simply what you can access-it is your spell catalogue slots rather than the few you select from the overall spellbook. It places you in a predicament at low levels if you find scrolls and must decide which spells to which you will limit your access.

So lets say you can use them multiple times until your life force depletes. A first level spell depletes your life force at 1%. So lets say using a first level spell gives you 1% chance of dying and becoming undead. You can use your first level spell once a round, but each use gives you 1% chance of becoming undead. Likewise a 9th level spell gets you 9% chance of depleting your life force and becoming undead. You wont become a vampire until 9HD so depletion of life force could be simply death for your spell caster at spell caster levels 1-8.

What does this do? It provides you with a limit on choices, not use. And it increases risk with power and over use. You wont want to use "teleport...teleport...teleport...teleport..." in your time as a powerful caster because each comes with a 5% chance of becoming undead. Rather your caster is more likely to use low level magic.

Now imagine no one knows that wizards/elves can go undead because they usually die from depletion of their life force due to excessively using magic before 9th level.