Commanding an unstoppable force of unrelenting automatons in devastating waves against your foes isn't how you will start out as a tinker. As with all adventurers, a humble beginning is in order. Wizards have their cantrips to change the flavor of food, fighters have their second hand swords and armor that ISN'T plate, and clerics eye scrolls longingly for those extra utility spells to negate the strange and wondrous afflictions they may encounter. You start out with a chunk of metal and legs. But let's start at the beginning and break down the numbers. Mostly this review will cover numbers and mechanics, because to be honest, anything else is just trappings. The specific appearance and manifestation of your mechanical army will probably be as various and interesting as the imagination of the player running the tinker.
This is a Pathfinder Class created by Interjection Games
Link to SRD: http://www.d20pfsrd.com/classes/3rd-party-classes/interjection-games/tinker
Link to Buy: http://paizo.com/products/btpy8yja?The-Tinker-Master-of-Modular-Mechanical-Mayhem#tabs
Base class information
Average hit die of d8, 4+Int skills, Cleric Base Attack Bonus, Reflex is the high save. Their armor is light their weapons are simple and they have basic shield proficiency
This is all pretty ordinary stuff. It seems about on par with things like the alchemist or wizard. The class is intelligence based, so 4+Int (which is low) isn't particularly crippling or anything. The skills that are class skills for the tinker include Use Magic Device, Linguistics, Perception and Disable Device as some noteworthy options. Also noteworthy, the Tinker only suffers arcane spell failure chance for armor they are not proficient with. So if you are proficient in heavy armor, you do not have a chance of failure.
Basic Tinker Gameplay
The tinker main focus is summoning automatons. These start out as small sized constructs with a size based slam attack and a pretty fair amount of Hit Points out of the gate. You can summon an automaton once per level per day. You have a maximum number of standard automaton's summoned based on your level, starting at 1 and topping out at 3. There are abilities that allow you to summon special automatons bringing you up to a total maximum of 5. However there are also abilities that allow you to summon more powerful automatons but have a lower maximum deployed.
Summoning an automaton is a standard action that provokes attacks of opportunity. When they are summoned they start with an order (referred to as a directive). Generally this will be to attack a particular enemy, but there are multiple base directives and some special unlockable ones. Giving a new order is also a standard action that provokes attacks of opportunity. Orders are given in a special language that acts like spellcasting.
Basic automatons are small sized mindless constructs. They have 10s in their strength and dexterity which are the only stats they have. These stats will improve as you level. They have a 1d4 slam attack and move at a speed of 20ft.
Basic Automaton Stats: http://www.d20pfsrd.com/classes/3rd-party-classes/interjection-games/tinker/tinker-automatons
These automatons are extremely basic and not particularly impressive at level 1. That said, their pool of hit points is far from inferior at this point, and anyone with a 1d4 basic attack can contribute at such an early level.
An example round for a level 1 tinker might go like this.
Move Action: Move to advantageous location.
Standard Action: Deploy automaton with attack order against a target.
Automaton Move: Moves to target.
Automaton Standard: Attacks target.
Some important points to note. Automatons are stupid (no intelligence score), they continue their order regardless of anything else going on. They will attack corpses, they will stand idly while they are attacked, they wont use special abilities of their own accord and they don't by default get attacks of opportunity. If a target dies, you will have to order the automaton to attack a new target, which is another standard action. Fortunately you do have the ability as a free action to order all your automatons to stop what ever they are doing.
Customization of Your Bots
This is the fun part. The automatons by default are bland, boring and will quickly become ineffectual without the true flavoring for your meat and potato minions which is inventions and innovations. Inventions are the special parts, gizmos and traits you give to your minions. Innovations are powerful effects that usually apply to all of your automatons. There is also another effect which improves your minions, the Master's Presence ability. This ability gives a passive bonus to all your minions attacks and defenses while they are within 30ft of the tinker.
Every automaton has a blueprint. A list of all the inventions cobbled together to turn your minion into the Frankenstein's monster of finely or poorly tuned destruction and creation. You start out with one blueprint, plus one more for every three points of intelligence bonus. It doesn't seem like much, but you will unlock more as you level up, and since you are an intelligence based class, a 16 is a very likely score you will be using. With a 15 you're probably also fine. At first level, you probably wont end up using more than one of your blueprints anyhow.
Each of your blueprints has a maximum build points total. This total is equal to your level. Each invention has a build point cost. The bulk of the early inventions are going to cost 1 build point. Later on the average cost will rise to about 2 build points with special and powerful inventions being 3 or more.
Each invention gives your automatons a new ability or trait. Some level one inventions are things like; arms, the ability to wield simple weapons (and a free simple weapon when deployed), the ability to be ridden like a mount and tweaks to accuracy at the cost of damage or visa versa.
An example level 3 automaton might have the following inventions.
Simple Weapon Proficiency (longspear) 1bp
Stout Design 1bp
This gives you an automaton wielding a longspear who's strength has been increased by 1 point and dexterity reduced by 1.
Innovations are abilities that really define what kind of tinker you are. You cannot change them like inventions and they apply to all of your automatons. Your first innovation is gained at level 2 and you proceed to get another every fourth level (2nd, 6th, 10th, 14th, 18th). This seems rather limited, however there is a feat to grant you an extra innovation. This allows you to scoop up other great innovations and really focus on your automatons.
Some of the innovations are basic boosts to all your minions, like Improved Construction which gives all your minions +1 strength and +1 dexterity. Some apply to specific minions like preferred blueprint which gives a single blueprint of your choice +1 HD. A few give the tinker abilities like Rapid Orders which allows the tinker to give directives as a swift action twice per day. And there are some that give the automatons new abilities, like my favorite, Kamikaze which turns your minions into self destructing mini fireballs.
Most innovations have requirements. Some are level requirements, some are invention requirements, and even some are ability score requirements. Be sure to check for those when planning your tinker's path to world domination.
An basic automaton without it's master is about as dangerous as your common lawn ornament. With a master's orders they can take up arms and march against their foe. But for really getting your minions going, you need to stay close and provide the encouragement only a personal touch provides. Master's Presence is an ability that gives your automatons a bonus to their attacks and defenses based on your Base Attack Bonus and Saves. Without it, most often your minions will be swinging their swords/bodies/tentacles ineffectually and inaccurately. Not only that, but given you can only give orders to minions within 60ft, staying close gives you the ability to maneuver and order more easily.
An example of the effects of master's presence at level 5 using a minion with no inventions or other bonuses.
Minions Normal Attack Bonus: +2
With Master's Presence: +5
AC without: 11
There are similar bonuses for saves and combat maneuvers, but lets not clutter this page with stat blocks. Needless to say, stay close, but don't get caught in the fire of your latest Kamikaze.
The Other Stuff
There are a few other cool things the Tinker gets later on in their career. Special automatons like the alpha, a bonus to crafting and greater innovations.
At level 4 they get an extra special automaton, the Alpha. This automaton has more build points in it's blueprint, has an intelligence score of 10 (so it doesn't require orders), gains feats and is larger than it's inferior counterparts.
However you must be more careful with this powerful automaton. Firstly, should it become destroyed it is VERY expensive to replace. Secondly, it's inventions can only be changed when you level up. Finally, you can never change it's feats after they are chosen (without taking an innovation to do so).
The tinker makes life (or the semblance of such) with his own two hands on a daily basis. This also happens to cross over into more mundane tasks. For every two levels the tinker gets +1 to all craft checks. This gets fun when combining it with minions specialized for assisting with crafting as it helps you to make more goods faster. Never underestimate the power of an industrial machine that doesn't sleep, eat or sweat.
Greater Innovations are innovations that are in every way better than normal innovations. These innovations cannot be taken with a feat, and are only granted at the levels 5, 10 and 15. They have powerful effects from granting all your minions large bonuses to their attributes, to allowing you to deploy another intelligent minion capable of doing activities independently while the master attends to more important (or safer) business.
The Sum of the Parts
The tinker is a highly customizable and unique class with a multitude of recombinant possibilities. Each tinker can go in with the same set of inventions and come out with a vastly different result. It gives you the opportunity to make your own summons. Beyond just the stock items you can find on the SRD there are a handful of supportive rules as well to expand the number of innovations and inventions available to your Tinker.