Back in the days of 1e and 2e D&D, when I played a magic user I would bend spells until they broke. I found ways to use spells that had little to do with their original intent but worked within their description. I drove GMs nuts with my descriptions of how my characters were using the spells because they'd would constantly need to make a ruling on whether it would work out the way I wanted or not. Things like casting an Enlarge spell on a wooden door in a stone frame so it would shatter as it grew too big for the space it was in, or casting a Knock spell to unlatch all the buckles on the enemy's platemail.
The newer games have either nerfed the spells or created far more explicit descriptions that don't allow for these interpretations of effects. That's progress I suppose.
I recently found myself exercising those old creative muscles again in a Fifth Edition game I'm playing. We're well into our second year of play and my Warlock hit 9th level. That means she can summon Elementals now. When I saw that ability as one of many on the menu to choose from at 9th level I thought about the Elric stories and all the things I could get an Elemental to do during the one-hour duration.
Now I look at the abilities of the different elementals and figure out what kind of things I can do with them. The reaction of horror from the other players when my character commanded an Earth Elemental to drag an opponent into the ground and leave him there was something of a surprise. I figure a Warlock has the moral flexibility necessary to bury imaginary bad guys alive.
Between the four kinds of elementals my character can solve a lot of problems. Combat and movement are two common ones. For instance, Air Elementals can carry your character through the air and blast your enemies. So much more fun than a regular Fly spell!
I've mentioned before that I'm working on my own fantasy game system and one of the priorities I have is to make the magic system more open. To design it to reward creativity and unconventional thinking. As wonderful as that is, it's taking a long time for me to test everything and make certain the game does all the things I want it to do (like be fun to play). Not to mention that a lot of people don't want to change their game even though they might like to bring what I'm talking about to their table.
The pulps that influenced the creation of the first RPGs leave their marks on the magic systems we take for granted now but the structure keeps magic safe and largely predictable. Magic was always a bit scary in those old stories. A good example of something that they brought into the structure is the creature from Robert Howard's first Conan story, "The Phoenix on the Sword," inspiring the Invisible Stalker spell. When you read Michael Moorcock's Elric stories though, they summon water elementals to create a fog to hide their navy or fire elementals to set fire to a town when attacking. They summon terrible creatures of chaos to get secret knowledge or help navigating the different dimensions. These creatures have their own agendas and goals. Sometimes negotiation is necessary and sometimes they simply oblige.
I know that Stormbringer has a magic system that works like this, but I don't play Stormbringer nor do I know anyone that does. What I think I need is an OSR/5e D&D compatible character class that uses magic from other creatures and does no magic other than summoning and binding them to the caster's will.
Using the Magic User/Wizard class as a base, we could get there pretty quickly. For whatever system you are playing in simply adopt all the hit dice, skills, weapon and armour restrictions, etc of the Magic User/Wizard class and swap out the spellcasting for summoning and binding magic that can be used any time.
This piece is actually my own attempt at drawing. I'm hugely jealous of people who can illustrate their own blogs so I'm going to try to learn to do this. If you are interested in my journey in that department or you want to see the links to the reference model you can see it at DeviantArt
This makes it easy to drop the class into whatever game you are playing without disrupting the game balance as it exists. If you are playing LotFP you get a character that can use any weapons and armour, like the rest of them but the lower hit points and lack of martial manoeuvres balances out the magic abilities. In 5e, the proficiencies and characteristics fit the flavour created by that system and its assumptions about setting.
Although for 5e, it might make more sense to use the warlock as a base for a summoner class. Once I've tested it out it would be nice to see if it would work for an Eldritch Knight. Elric was a warrior first. He only summoned elementals for large scale effects or to save him from drowning. He fought for himself.
The magic of summoning should be accessible but dangerous. Since the entities often want to get to our world for whatever reason summoning them should be easy while the real challenge comes when trying to control the creature. I also like the idea that it gets more difficult to control new entities throughout a single day. That way there's a good reason to conserve the magic and use it only when it's needed. That escalating danger is a good reason for characters using this kind of magic to be universally feared by ally and foe alike.
I already have summoning magic baked into my own game and tests are going well so far. I'll be putting together an OSR Class for summoning soon, but since I'm playing mostly 5e and playtesting my original game I'll probably do one for 5e D&D first. If you beat me to it, send me a link!