In Arcane Summoners, a terrifying elemental beast has been summoned by a dark sorcerer. Each player is a mystical summoner with the goal of summoning their own elemental heroes and be the first to defeat this main boss. Each hero has a different elemental type and strength (as indicated by the number of spell cards they allow their summoner to draw) and some of the them have special abilities that either help their own summoner or sabotage the armies of fellow players. Depending on the elemental type of the boss (which is different each game) players will try to summon complimentary types of heroes in order to get bonus multipliers on their spell cards. The first player to attempt to defeat the boss and amass at least 100 points worth of spell cards wins.
Above is the game board. It shows which elements trump each other and it has movable markers so that players can keep track of the current elemental bonuses for that game. In this example the boss is a fire type, so water cards are worth double the points because water is stronger than fire and earth cards are worth half. On either side of that are summoning towers. This game utilizes an Uno deck, with the cards having new meanings. The color of the Uno cards correspond to different elements (ex: red cards are fire type). Any Uno card with just a number on it is a spell card. In order to summon a hero you need to place two spell cards of the same color on the corresponding tower (ex: a blue 7 and a blue 2 can be placed on the water spaces to summon a water hero the following turn). That means each tower has room for up to two people to summon at once.
Reverse cards let you change the elemental type of someone else's hero to the color type of the reverse card. Skips let you block two spaces on a tower so no one can use it to summon until after your next turn. Wild cards let you change one of your or someone else's heroes into any other elemental type. Draw cards just let you draw more cards immediately. Each turn a player draws 5 cards, plays as many as they are able and would like to play and discards anything they don't use. Any cards placed in towers come off the board at the beginning of their next turn and they receive their heroes from the hero decks.
When a hero is summoned the summoner takes the top hero card off the corresponding deck to the tower they used. Next to the hero's name is a number which represents how many spell cards of that color can be drawn when trying to defeat the final boss. For example if I had Hastur (pictured above) he is a yellow/air hero with a +4. That means that he allows me to draw and keep the first 4 yellow spell cards from the top of the deck. So if I drew a 4, an 8, a 2, and a 0 I would have a total of 14. And since the board tells me air cards are x1, my total is still 14. I need a score of 100 or higher to win the game. So ideally you try this when you've summoned lots of heroes, hopefully ones that are worth double.