Hellenic Secret Society Woes

Here's the short version:

It doesn't matter which religion we're dealing with AFAIK.

Have high diplomacy.

Don't have low diplomacy.

Unlanded characters are much easier to recruit - try to convince the spouses of rulers, so they can convince the ruler's heir to join.

When you're just starting, focus on high-diplomacy courtiers. High diplomacy makes them better at recruiting, and being courtiers makes them easier to recruit.

When making someone sympatheti:

The family argument works well against almost anyone with children.

The personal argument works well against friend, lovers, relatives, and people who otherwise like you.

If you want to induct someone into the faith, choose based on their education or lifestyle, unless both are intrigue. You can also go for community if they have kids, friends or lovers.

If you still don't know, start looking at traits - Brave, Gregarious, Erudite, Ambitious and Just are the ones that matter.

No matter what nothing will work against religious heads.

Be gregarious. It helps a lot when trying to convince people to stick around.

And here's the long version...

For developing sympathy, it always helps if the target is Kind, Just, Trusting, Patient or Charitable. Odds also improve when your diplomacy is above 12, 14 and 16.

As for the arguments, each argument is improved if at least one of the following is true:

Family

Gregarious

Socializer

Kind

At least one friend or lover

At least one child, if opinion is at least 35 (not sure if that means the child must like the parent, or vice versa)

Trauma

Craven

Kind

Scarred

Has any disease, disability, or negative congenial trait.

Profit

Greedy

Ambitious

Cynical

Administrator

Diligent

Smart, Genious or Shrewd

Any stewardship education

Personal

The target must have at least 15 opinion of you for this bonus. In addition, one of the following must be true

Target is your friend or lover.

Target has at least 50 opinion of you.

You are the target's direct liege or top liege.

You and the target are close relatives.

You have at least 15 diplomacy.

Each of these make the AI less likely to become sympathetic:

Target is Zealous

Target is Cruel

Target is Arbitrary

Target is landed (harder for higher tiers)

Target is a priest.

You have less than 8 diplomacy

Religious heads will never develop sympathy this way.

Trusting characters are always more likely to join the religion. Your diplomacy also helps (odds improve every two levels from 12 to 22). You can never convert the head of any religion. As for the different options:

The warrior option is more effective if at least one of the following applies (they don't stack)

Brave

Any martial education

Any martial lifestyle (I think that means duelist or strategist traits?)

Target is someone's marshal

The community option is more effective if one of the following applies:

Target is Gregarious

Target has at least one friend or lover

Target has at least one child who likes them or who they like, again not sure which

Target has a diplomacy education

Target has a diplomacy lifestyle (not sure what this includes)

The theology option is more effective if one of the following applies:

Target is an Erudite

Target has a learning education

Target has a learning lifestyle - not sure what this includes either.

And the legendary ruler one is more effective if one of the following applies

Target is ambitious or just

Target has a stewardship education

Target has a stewardship-based lifestyle

Targets are less likely to convert for each of these:

Target is a priest

Target is paranoid

Target is zealous (this is a big one)

Your diplomacy is below 8

Target is landed (it gets a lot harder as their rank goes up. Except against nomads.)

Credits to u/pjoelj

/r/CrusaderKings Thread