Zen Archer / Synthesist critical rule question

[Zanlith]

Hello guys, I am playing in a d&d with friends. I ,made a synthesist 1/ monk (zen archer)3. We had some arguments about Flurry Of blows.

Zen archer FoB at lvl 3 is +1/+1 and synthesist has +1 BAB at lvl 1.

I tell him that when I use a normal attack I have +1BAB (because synthesist has his own BAB). But when I use FoB I have +2/+2 because flurry of blows adds monk lvl to my BAB. Please clarify this to me and explain why as well :) Am I right or wrong?

Thanks in advance for your interest!

[Toirin]

Actually, when you normal attack you would have +3 Bab, 2 from monk and 1 from synthesist. Then you are correct about the +2/+2 when flurrying because you use your monk level as BAB (+3 instead of +2) and -2 to each attack from TWF. This gets really confusing when you make it to +6 BAB when flurrying...

[Zanlith]

Toirin wrote:

Actually, when you normal attack you would have +3 Bab, 2 from monk and 1 from synthesist. Then you are correct about the +2/+2 when flurrying because you use your monk level as BAB (+3 instead of +2) and -2 to each attack from TWF. This gets really confusing when you make it to +6 BAB when flurrying...

It says:

The synthesist uses the eidolon’s base attack bonus, and gains the eidolon’s armor and natural armor bonuses and modifiers to ability scores.

So my attacks while fused with eidolon are with eidolons BAB(+1). But I want a clear answer if my bab is changed when I FoB (do I add my monk lvl to eidolons bab?).

[Mojorat]

Your bab with eidolon you is +3. +2 for Zen archer +1 from eidolon. When you flurry your bab becomes +4 and you apply twf penalties. So +2/+2 the fact that it becomes +4 before penalties is important as Anything that uses base bab like deadly aim uses this number.

Basically a synth 1 fighter 19 with the eidolon up has a bab of +20. For relevant faq look for a monk flurry of blows faq on the same issue.

[Artanthos]

FAQ

FAQ wrote:

When fused, use the eidolon's BAB instead of the summoner's class BAB, and add in BAB from other sources as normal. For example, a fighter 19/summoner 1 normally has a total BAB of +19 (+19 from fighter, +0 from summoner), and when fused with his eidolon this increases to +20 (+19 from fighter, +1 from the 1st-level eidolon).

FAQ #2

Quote:

A monk using flurry treats his BAB from monk levels as equal to his monk level. He still adds BAB from other sources (such as other classes or racial Hit Dice) normally to this total.

So a fighter 19/monk 1 has a normal BAB of +19. When he flurries, he treats his monk BAB as +1 (for his 1 level of monk) and still gets BAB +19 from his fighter levels, for a total flurry BAB of +20.