I was asked by Nakago Yaiba to suggest a system of stats for summons and suggestions of how to use the stats. I found easy numbers to use in order to still have enough room to play with, and large enough to make them formidable.
Special Reminder: Think of Summons as not controlled by you, but instead are free standing PC's. They need to be strong enough to keep up with you, and smart enough to know what and when to do something. A well rounded summon is important just like a well rounded Shinobi.
Special Reminder Part 2: Summons do not have fighting styles, so in order to have any stat above 100, they actually have to have that stat above 100 or a jutsu that sends them over it. So Summons are not bound by the only to 100 Rule.
Exceptions: Within reasonable means, these numbers can be changed based on the contract if accepted. These means can be special types or methods of summoning, enhancing means, or any assortment of this type, deemed acceptable by a mod.
Minor Summons: D,C,B
Minor summons are some of the best to play with, since you can make so many of them, and have them set for what ever you are in need of most. These are good for practicing to see what would work best with you.
D Rank: Think of these as Shinobi Academy Students. Can't do anything really, except maybe be friends with and eventually grow into the masters later. Basically, since C rank is needed to summon anything, a D rank summon is a failed summon. Congrats! Give about 100 stat points or less here.
This is a pointless summon, don't make it please. Just an example of Naruto trying to summon toads at the start.
C Rank: Most summons will fall into this rank. The Genin of the summon world. Strong enough to do damage, but not strong enough to take over the world. Remember, you can spurge on one stat, but then the others will be affected greatly. Give about 220 stat points here max.
(Suggestion: Well rounded is best)
B Rank: The elite of the Most Basic Summons. This rank of summon is still basic, but strong enough to do some real damage. They are equivalent to Chuunin. And just like any Chuunin, they have found their Role, and are strongest at particular abilities and stats. Give about 270 stat points here max.
(Suggestion: If you want a Strategist, increase wisdom, if you want a Str Fighter: Strength and dexterity should be highest. But it is also good to have a decent amount in other stats, you never know when you might need that Str fighter or Strategist to chase/run to support, or to be able to take a hit.)
Major Summons: A-S Rank
Major Summons are the gravy of the contract. Hopefully you know what you need most, and this is where you put it. The ultimate support team. Usually Major Summons control the battle field, and are a force to be reckoned with.
A Rank: Most Summons will never go beyond this rank. Though, there will always be a few of them around. Strong enough to be capable to support the strongest fighters of our world, but not enough to take them on without help. Think of these as the Jounin of the summoning world. Give about 330 Stat points here.
(Suggestion: These are the ultimate forms with a given Role. Suggest only 1 stat goes above 100 or 2 get close to it, the rest for rounding the summon off.)
S Rank: Almost the Best of the Best in the summoning world. These guys here could give most of the super strong shinobi a run for their money alone. They would give Boss Summons a very hard time. Think of these as the Jounin ANBU of the summoning world. Give about 370 stat points here.
(Suggestion: These are a step up of the A rank, and a minor one at that. They have a few more points to go into what would make them just that much better at what they do, or perhaps to make them last longer or be able to change tactics in a fight.)
Boss Summons: SS Rank
SS Rank: The Best of the Best in the summoning world. The "Boss" of all summons in your contract. And just like any boss, "There can be only ONE!" (que lightning and massive earth shattering wind) Take your time when making this guy or gal, because chances are, unless you kill them off, you aren't getting another one. And if you kill them off, unless all the summons hate each other, they will distrust you for killing them. This summon is strong enough to get close to taking on the best decent shinobi in our world, and maybe strong enough to assist you when taking on the Unknown that lurks in the shadows. This is the Kage of the Summoning world. Give about 400 stat points here.
(Suggestion: Really take your time when making this summon. You can make him/her have some sort of special abilities using techniques with any form of Combat Skills needed. All the bells and whistles you would want for either being solo, or being support. So well rounded is in much need, but don't go overboard, you should have 1-2 stats that are at or above 100.)
Special Summoning Jutsus:
This is my favorite form of using the summoning contract, yet the most difficult. Here I will use two examples of jutsu used from Canon. Summoning: Quick Beheading Dance (Temari) and Binding Snake Glare Spell (Sasuke/Orochimaru). This basically calls out the summon, and without it needing commands performs a said action. The weasel slashes everything, the snakes bind.
Summoning: Quick Beheading Dance is a B-Rank technique. So let us use a B rank Summon’s Stats, 270.
Strength: 35
Constitution: 30
Stamina: 30
Agility: 75
Dexterity: 60
Wisdom: 40
Now this might be a good example of this Weasel summoned straight out normally. Strong enough to chop through a tree with weapon, able to take a hit, enough chakra/energy to do a few jutsu, enough agility to move faster then the eye can see, enough dexterity to move that sickle around quickly to go from one target to the next quickly, and smart enough to know what it is doing. Now the technique it is using along with this, could increase speed, agility and strength somewhat, let us say 20 points each, an A rank jutsu. This would give a good execution to do what it is meant to do, slash everything in half and do it quickly.
The downside here is the summon isn't smart enough to tell the difference between enemy and allies, especially at the speeds it is moving. Now this maybe just be partially because of having 1 eye, or personality of the summon (maybe it don't care) but...lets just say because of the speed and intelligence.
This summon could be used as a regular summon as well, fairly well. So it can summon a dual purpose, of a summon attack, and just as a regular summon.
Binding Snake Glare Spell is a C-Rank technique. So let us use a C rank stats, 220 points.
Strength: 70
Constitution: 30
Stamina: 20
Agility: 30
Dexterity: 45
Wisdom: 25
This would be an example of what these summons could do if summoned normally. Strong enough to restrain most targets, enough dexterity to allow body to bend around target, fast enough to do the job in a short distance quickly, and smart enough to do what they need to. For the poison bite, you would have a jutsu that supplies this. And for added strength, maybe a jutsu that increases the strength by a small number.
Though as you can see, if they were used at a great distance or for a general summon purpose, they be very ineffective against a semi decent opponent. They are slow and not very smart, so they couldn't react quickly to an approaching force or someone not close by. And if they were attacked from an outside source during the binding, they would easily be beaten. They aren't able to use many jutsu, or hold out on a strong jutsu for very long. They serve their purpose pretty well non the less. But if this snake was fighting a genin or so, it would be an equal match for the most part, but leaning a little towards the genin.
Fate:
Um, IDK really for this stat. I haven't had enough (any) encounters of using it just yet. I would say use it the same way as for shinobi, higher for bosses, lower for basics. Maybe a 2,3,5,6,7?