第一天，祖母被唤醒，说书人告知他一名善良玩家和他的具体身份，当这名玩家被杀害时，祖母会一起死亡。
在第一个晚上，祖母醒来，得知她的孙子玩家A是教授。三天后教授被恶魔杀死，祖母也死了。
祖母知道她的孙子玩家B是赌徒。赌徒赌博并因此而死。祖母不会死亡。
祖母知道她的孙子玩家C是修补匠。C被恶魔杀死了，但是祖母因为水手的缘故喝醉了，所以祖母不会死亡。
Protect your beloved grandchild! They are definitely good and a Townsfolk, and that is a certainty that is rare and precious in Bad Moon Rising. Also, if they're killed by the Demon, you will die too - extra motivation!
Talk to your grandchild, feed them cookies, and get them to trust you! Unlike similar characters like the Washerwoman, your information is so absolute since you only learn one player and their identity - there's no benefit to getting them to admit who they are first unless you sincerely doubt your sobriety. When you get a chance, reveal that you know their character and how, and you guys will have a lot of trust from the get go.
Don't reveal the identity of your grandchild to anyone! If the evil team know how you are connected, they'll absolutely want to kill them and score your death as a free bonus. Keep them secret to keep them safe.
Reveal your identity and your grandchild early to a couple of players. This has a couple of bonuses - if these people are trustworthy, they will know to trust you and your grandchild in turn. If you and your grandchild suddenly die, however? You can look at these players with great suspicion - it's possible that one of them is actually the Demon! (Note: If you suspect you're talking to evil players, you don't have to tell them who your real grandchild is...)
There's many ways to build trust with the good team using your information!
Encourage protective characters to cover your grandchild. If you know the identity of an Innkeeper, or your grandchild is close to a Tea Lady, try getting things set up so that your grandchild can be covered at night, keeping both of you safe.
Similarly, you can warn away players like the Sailor and the Exorcist, who will be making your grandchild drunk OR just wasting their ability on someone you know for certain is a good Townsfolk.
Finally, you can encourage the Gambler and the Chambermaid to use their abilities on you or your grandchild, allowing you guys to trust each other when your information lines up!
If you and your grandchild are the only ones to die at night, you probably died because of your ability. If you suspect this is the case, make sure to let the good team know, as otherwise two deaths at night is an early indicator that the deadly Shabaloth or Po is lurking, when in fact the Zombuul or Pukka are still very viable options.
Don't talk to your grandchild right away - whispering together, especially in the early days of the game, will attract both good and evil attention, and a Demon may just pick you two off on suspicion that you're Grandmother and grandchild.
Reveal to the group that you are the Grandmother, but without saying which player your grandchild is. For example, you can simply say "I am the Grandmother, I know there is an Exorcist in the Town", or something similar. This lets the group know that you are a Townsfolk character, and also lets them know to expect an Exorcist to reveal themselves at some stage.
The easiest way to bluff as the Grandmother is to claim that you are the Grandmother, and claim that an evil player is your grandchild. You probably won't want to do this on the first day, since most Grandmothers take a day or two to reveal their information. Waiting a day or two also gives your fake grandchild a chance to tell the group who they are, so you can copy them. Or, you can simply say that you are the Grandmother, declare that an evil player is a particular good character, and hope that they see what you are doing, and clam to be that character too.
Convince a good player that you are their Grandmother. This is easiest to do if the good player has revealed their character to you beforehand, or revealed their character publicly. If you know their character, you can tell the group the same thing. If you don't know their character, you can have a guess... or refuse to say anything at all.
Ask your fellow evil players to secretly find out which good players are which, and to get this information back to you. Once you know the identity of a good player without that good player knowing that you know, it is much easier to convince them that you are their Grandmother.
Bluff as the grandchild! You can claim to be a good character and still claim to be the grandchild. Tell the group that the Grandmother has approached you privately, and you trust them completely. Hopefully, an evil player will later claim to be the Grandmother and corroborate your story.