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OCD are a small games design company based in SE England. Our flagship product is the obSESSION Cross-Genre RPG System but we also make a small number of card games and have plans for further expansion.

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These rolls come in three forms: Skill Rolls use your Character’s Rank in a Skill to determine the size of the Dice Pool; Attribute Rolls use the Skill Value (SV) of one of your Character’s Attributes to determine the size of the Dice Pool; Combined Rolls add the dice from a Skill Roll to the dice from an Attribute Roll and use the total as your Dice Pool.

Since all Dice Pool Rolls function the same way, these distinctions exist purely to let you know how to build your Dice Pool. The results are the same whatever type of roll you make and the three types exist primarily to make life easier for GMs and designers. Combined Rolls are the easiest to make and are probably the most common type in most games.


Actions, Rounds and The Tactical Environment…

The Tactical Environment is the flashy, and somewhat pompous, name we give to any activity where the timing of events is particularly important. The most common example of this is usually combat.

Within the Tactical Environment we divide all activity up into easily managed Rounds, which last ten second of in-game time but usually take rather longer to handle in the real world. During a Round each Character, Monster or Artefact (we normally abbreviate this to C/M/A, by the way) can perform up to five Actions. The order in which these Actions take place is determined by Initiative, which is itself determined by a combination of the C/M/A’s Reflex Attribute and an Attribute Roll using Agility. Unlike many RPGs, obSESSION™ uses a system where the lowest Initiative acts first. For Players used to other games this may take a little getting used to but it helps if you think of Initiative as the time it takes to complete an Action; the Action which takes the least time is completed first. In fact, that’s exactly how the obSESSION™ Initiative system was originally written and that more detailed system is available as an optional rule.

Sometimes a GM may want to use initiative without entering the Tactical Environment and this is fine. Simply roll Initiative as normal and then use it to determine only the order of the Actions in question.


Threshold Numbers & Success Targets…

All tasks are not made equal and so obSESSION™ does not treat them as such. Jumping over a two-metre pit is easier than jumping over a four-metre pit, climbing a brick wall is harder than climbing a rough rock wall. To deal with these matters the game uses Threshold Numbers and Success Targets.

When we explained Dice Pools we said that each die which rolled over four was a Success. This is because the “standard” Threshold Number (TN) for Dice Pool Rolls is four. Circumstances can change this however and you always need to roll over the Threshold Number. As you can imagine, this means that a roll with a TN of 10 or higher is impossible to succeed.

Success Targets (ST) are a slightly different beastie. Rather than changing the TN, the GM can decide that a task can be achieved only with a high degree of competence and assign it a higher ST instead. This indicates the number of dice which must exceed the TN in order for the task to succeed. It should be immediately obvious that higher ST Skill Rolls can only be accomplished by higher Skill Rank C/M/As.

On To The Good Stuff…

If you looked over page one then you now know that obSESSION™uses Dice Pool Rolls to determine the success of your Character’s actions. What you don’t know is how to determine the number of dice that are actually in a Dice Pool.

Rules Vs Setting….

Because obSESSION™ is a Cross-Genre game system, not a complete RPG, it is necessary to plug that ruleset into a playable environment or Setting before you can play. The easiest way to create a setting is simply to model it very closely on the real world since this requires very little work on the GM’s part. The Players already know the basics and the “rules” of the world in which they live so they don’t need to be told about them. OCD have capitalised on that when creating our range of Capsule Settings, using the existing world as a base for more than one in order to minimise the detail that needs to be in the Capsule, and you can do the same thing for your own games if you wish. Alternatively you might create a setting based on some other milieu which the Players already understand, such as a favoured book or TV series. Fantasy RPGs usually rely on the Players having at least a passing familiarity with the work of authors such as JRR Tolkien, George RR Martin or Brandon Sanderson while science-fiction games borrow concepts from popular films as well.

OCD have a full range of Capsule Settings and complete games planned for use with obSESSION™, some of which can be used with other games and some of which come with all of the rules included and do not need the obY “Core Book”. There is no need for you to use these settings however, you can always create your own and, because of the internal consistency which OCD pride ourselves on, you can “borrow” elements and mechanics from any existing sources.

When creating your own settings you will want to pay attention to what are called the Core Attributes: Reality, Magic, PKE and others. These Attributes shape the way in which the world works and are designed so that you change them, rather than the rules, when you want to make things a little different in your setting.


FX and Weird Powers…

Many of the Core Attributes, including Magic and PKE, exist in order to shape the way that special powers work in the world. The Reality Attribute, if higher than zero, makes such powers harder to use and these Attributes serve to make them easier again. This lets you tailor a setting towards certain types of powers.