If I use Margaery Tyrell to kneel Black Hatchling who cannot defend,what happen?

I think Black Hatchling can be kneeled,but don't count it's Str.

thanks.

I think it'll be a defender and count its Str, Margaery is adding it to the challenge outside of the normal timing much like neutral card "The wall" or bouncing Catelyn can be added to challenges.

Note she can be used on characters without the proper icons to make them also take part in challenges so yep im 99% sure this is right.

Reading black hatching though, i thought it was cannot be declared as a defender but its cannot defend...

So since cannots are absolute, im now 99% sure ive no idea.

Lala, ignore this, trying to edit and quoted myself...

The relevant text is:

Black Hatchling:

Black Hatchling cannot defend

Margaery Tyrell:

After Margaery Tyrell is knelt as an attacker, choose and kneel a character controlled by the defending player. Then, that character is participating in this challenge as a defender.

Margaery's ability has two parts: The one before Then, and the one after. There's no doubt that the pre-Then part can indeed happen to Black Hatchling. He cannot defend, but he can be chosen and knelt.

The post-Then part, however, cannot apply to the now knelt Black Hatchling. As totalgit says, "cannot defend" encompasses more than just being declared as a defender. It means that the character cannot be made a participating character on the defending player's side in a challenge by any means.

So basically yes, Margaery will kneel Black Hatchling, but he will not be made to participate in the challenge.

Rat's explanation is spot on.

Black Hatchling's "cannot defend" is like the "cannot defend" that happens to a character bypassed by Stealth. Following the way that using stealth to bypass Greatjon Umber or characters with a naval enhancement goes, we know that card and game effects cannot pull "cannot defend" characters into challenges as defenders. Therefore, Margaery's "then" effect will not successfully pull a "cannot defend" character into the challenge.

And, as Rat point out, because the defending is part of the "then," not part of the "choose and kneel" of her ability, the inability to defend does not make the Hatchling an ineligible target for her ability.

End result, the Hatchling kneels, but it does not participate/defend. (That's not quite the same thing as snowfrost's original thought; not participating as a defender at all goes deeper than not counting its STR.)