In the early stages of Tensai's design (well, early is relative, I spent less than a week on the actual core systems design on Tensai before going straight into content design of moves, creatures, and the items), I made the decision to give each creature two equippable items: a Weapon and a Trinket.
Trinkets were essentially Pokémon held items. There were analogous ports such as my own version of Leftovers, Life Orb, and the Choice items from Pokémon, but of course... because of the good ol' trusty ACTION TYPE SYSTEM I've been beating an entire graveyard of dead horses about... there were some unique additions to the system.
The Primordial Switch and Reversal Charm trinket would be announced when a critter holding them swapped into battle, because their effects were QUITE important. The Primordial Switch trinket reversed the elemental hierarchy (so Fire would no longer be strong against metal, ice, and wood, but instead be strong against rock, water, and air.) The Reversal Charm would do the same for Action Types, reversing the flow into the opposite direction.
Pokémon's Arceus “Plates” made their own analog home in Tensai's treatment in the form of Amulet trinkets, which boosted the power of elemental damages by 20%. Of course, since elements aren't the only damage types it meant I also got to make Trinkets for...ACTION TYPES! These trinkets carried a bonus effect in addition to boosting damage of that Action Type: the creature holding that item would enter the battlefield in the Stance of their Trinket. (This Stance ONLY applied on entering the battlefield, not when idling on a turn, so if a Creature had a passive stance already, the Trinket wouldn't overpower the Creature's innate ability.
I tried not to go too heavy-handed with Trinkets, and stick close to the proven designs from Pokémon; with plans to balance or make additional creations/subtractions after playtesting to see what worked and what didn't. With trinkets out of the way, it's time to talk about the other items: Weapons.
I created the Weapon slot as a second answer in addition to Action Types to help alleviate problems of being in an elementally disadvantageous situation. Basically, Weapons were a generic move that is available to all creatures, regardless of their element. There were Rods, Halberds, Shields, Clubs, and Slingshots (to represent Magical, Aerial, Defensive, Melee, and Ranged action types) of each of the seven elements as generic 25 Essence-cost moves.
The general expectation behind the standard weapon choices was that players would look to equip a weapon that fully covered their type weaknesses (A Fire creature would want a Wood weapon to have strength against Air/Water/Rock creatures that counter it.) Of course, with Pokémon moves like Toxic, Substitute, and Rest being prevalent in TMs and able to be learned by nearly all Pokémon, there were weapons like the Kitchen Knife, Decoy, and Panacea respectively to translate those moves into a Weapon option for critters of Tensai, at the opportunity cost of type coverage.
But the buck doesn't stop there for items. I'd added one additional battle command option for players that didn't exist in Pokémon: The ability to swap items between your Critters. For example if you had an active creature that was getting low health (but likely able to survive an idle turn), you could swap your damaging weapon with a Panacea to fully heal and fall asleep for a few turns. If you had a creature with the Flying passive (Aerial Stance) that also relied on Aerial moves for its best damage, and had reason to fear your opponent's ranged moves, you could use your turn to swap your Trinket for a Reversal Charm held by another member of your team, adjusting your strategy on the fly.
If you wanted to bring in a creature with a Choice item in Pokémon, after using the move you are locked into using that same move until you swap out the Pokémon, sometimes losing a type advantage you'd backed the opponent into just because you couldn't undo your move selection. With the ability to swap items in Tensai, bringing out a creature with a Curse of Speed (Choice Scarf) could enable you to use your superior speed to knock out an enemy, then instead of swapping out your creatures, simply swap your Trinket to another member of your team, freeing up the ability to use any of your moves. While it would cost you a turn, you would not forcibly lose any positional advantage you had earned through the use of the Choice item.
The ability to change weapons also gave one other option: to sacrifice the elemental advantage your weapon was intended for to ensure you had Action Type coverage over your opponent's creatures after scouting his moves. Say, for instance, your opponent favored a Magical move for damage, and you did not have a Melee move in your creature's 3 move set, and currently had the Flowing Halberd (Water Aerial) weapon equipped. You could trade the Halberd to a creature with the Stone Club (Rock Melee) in order to get access to a move to negate the incoming damage of their largest threat, either forcing them to use a less efficient move by threat of you having a counter or forcing them into a game of chicken.
This ability to trade items between creatures could allow a player to cover situations their team was not truly prepared for by giving creatures action types that weren't prepared in team creation, and created dynamic customization as the battle unfolded.
I was a bit worried that even with the weapon slot, players might feel only 3 moves per creature was a little underwhelming, so I also made sure to design each creature with its own Signature Move. The giant flaming bear zodiac (I'll go into this when I talk about the world design of Tensai) creature Guiredaro had the ability to use Bear Hug, grappling its opponent and transferring any other negative status effects from the user to the target. Guiredaro was designed around setting himself Aflame (a damage-per-turn status effect) and then transferring that status to the opponent. The other fire zodiac creature, the Firefly, was designed around setting itself Aflame to heal itself, as fire-elemental moves healed it. Its signature move, Burn Up cured negative status effects and THEN set it Aflame.
One of the metal zodiac creatures was a squirrel themed around magnets; its signature move was called MagLev, which inflicted the status effect “Juggled” for one turn – a status effect that tied back into my Action Type system by ensuring if an Aerial move hit the target next turn, it took double damage (similar to a critical hit, only specific to one Action Type). If your creature was Juggled, you had to be extremely wary of an incoming Aerial attack. So you could prepare a Ranged attack...but again, the layers upon layers prediction come forth.
By making Signature moves for each of the creatures, it also adds a specific expectation of what the Action type that creature will use for its primary damage source once a player becomes familiar with the game. If you see a Guiredaro Aflame, you know he wants to Bear Hug you, a melee move. This preconceived expectation of a player's moves helps dictate the flow of an average battle, but as players become more intimately familiar with both the game and one another, it adds inherent depth into the possible interactions.
Combined back with the ability to swap out items, the semi-scripted nature of battle created by Signature Moves helps allow a player know what's coming before it comes and prepare for it by getting their items where they needed to be before they needed to be there. Or after. Whatever.
Regardless, the Action Type horse army has been sufficiently beaten to death, so my next blog on Tensai is going to focus on something else. Not sure yet what it will be. Could be the Astral Gate world in which Tensai is set (a fantasy world I've been worldbuilding for nearly 6 years now.) Might be just the Zodiac alone. We'll see when I get inspiration to write again. Thanks for reading!