|With Lancina, (Lance Lucina), she is now the fastest Infantry Lance user in the game 36 speed neutral. 39 if she has a speed boon. 40 if it's a Speed boon, +1. a 50/40 Atk/Spd distribution is pretty strong.
'"`UNIQ--item-424--QINU`"' is probably her best weapon, as it has 16 might, buffs physical attackers, and grants Lancina 3 more def. Making her def 30. There might be no other weapon better for her than this.
For an assist skill, it's really up to you. '"`UNIQ--item-427--QINU`"', Rally assists, etc.
I know that Lancina comes with '"`UNIQ--item-430--QINU`"', but that will take too long to charge. So, for this build, '"`UNIQ--item-433--QINU`"' is a better choice because it takes 3 charges, and you can make that down to 2 with '"`UNIQ--item-436--QINU`"'. However, there are typically more desirable units to use Quickened Pulse on, so it's not necessary. With her solid Def, she can take hits from other lances and axes, charging up Luna easily.
As this is supposed to be a low investment in my opinion, for her A skill, go with the default '"`UNIQ--item-439--QINU`"' As it will boost her attack to 54 and her defense to 34. That way, she can do more damage while at the same time, take less.
She doesn't have a B skill, so I would say give her '"`UNIQ--item-442--QINU`"'. The reasoning for this is that, even though her Spd is high, this still acts as a failsafe in case other users can double her while allowing her to double them back regardless.
Her C skill should be her default '"`UNIQ--item-445--QINU`"' as it gives units +3 speed in a 2 space interval, meaning that a unit can be in a close diagonal to her, and that unit will get the bonus.
Considering team options, if you have Lancina on your team, having a magic check on the team is a must as any kind of mage will make a dent to her health, even the red ones. It's even worse when she has a Resistance Bane (which is her preferred bane though as she already has low Res). It's also important to have a strong check against green units as well as they can easily defeat Lancina.
Basically, this kit is for those who are F2P players. It's low investment and you only need to inherit 2-3 skills. With this build, you'll be able to take down almost every red in the game. May your strategy lead you to victory! - Hoodlum212