Found these two quests extremely simply with these 2 strategies.

For the Towards Truth 2, the 2 vs 1 fight. Just create a deck full of 1 Atk point monsters and through in a few split boosts, slashes, roughly 6 action cards no defense. 2 or 3 Dice +1's and as many March of the Meek's as you can. Simply block the two opponents from the start, Sil'fer will stand still for the majority of the fight, just bait her with 1 monster at a time and she'll stay still and attack it. Eventually she'll die because most of her weapons have Steady Damage which will hurt her, kill her mags and daggers if you want and she'll eventually equip 2 Steady Damage weapons. As for Kranz simply keep swarming him with attacks, he'll soon run out of weapons and be open for attack. Any SC is good for this, KC is pretty good though because he can stay behind the monsters and shoot.

This is adapted from the guide already on the site, which I used to create a deck for my first Castor and Germ fight.

Deck to use: (Hyze)
2x Sinow Red
2x Dubchich
2x Dice +1
24x Action cards

About 7 or 8 defense cards consisting of Guards, Resist and whatever else you want, I used Reduce. For action cards put in lots of Attack, Stab, MC Attack and Slash, then cards like Split Boost, Heavy Attack, Beat and Assault. This will allow you to do powerful combo's.

For Castor just attack with Sinow Red and Hyze, your combo's will do up to around 15 per hit. Remember she can attack up to 3 or 4 spaces in front of her hitting multiple enemies. With this in mind just go up to her and she'll die quickly.

For Germ, set down Sinow Red and Dubchich when you can, attack with dubchich first always to waste the enemies defense card. The Germ only has 4 ap and Dubchich heals to full health every go, so you dont even need to defend in this fight really. His guard creatures will die in 1 round from your attacks. I got an S rank with this deck first time I tried the Germ.

Sorry if any of this has been posted before.