Gain 10% CDR when you reach level 10. Excess CDR becomes AP or AD, Adaptive.
Offense
+5 AD or 9 AP
Flex
+5 AD or 9 AP
Defense
+6 Armor or 8 MR (match-up)
WhyAftershock
Aftershock on Lissandra allows you to hard-engage with [E]->[W] and get a bunch of defenses until you [R] and Zhonya's, making you unkillable for a long period of time.
WhyFont of Life
Lissandra's [P], [Q], [W], and [R] all apply AoE ccing empowering your teamfight and skirmish power by proccing Font of Life on everyone.
WhyBone Plating
Bone Plating's burst damage reduction is great for those moments when you engage for your team and are not able to get a self [R] off immediately.
WhyRevitalize
Revitalize on Lissandra is great for empowering your self-heal from casting [R] on yourself.
WhyManaflow Band
Manaflow Band is fantastic for empowering your ability to poke down your lane opponent.
WhyTranscendence
Early CDR is especially useful on Lissandra and is results in a lot more damage throughput from [Q] and well as CC with [W].