Friend of the Elements

Your friendship with the elementals of this world has granted you with special abilities:

You learn the Conjure Minor Elementals spell

Additionally, you have learn how to cast it with lower level spell slots: When casting the spell with a slot lower than 4, halve the number of elementals you can summon, rounded down to a minimum of 0. -

Lastly, you may cast it once at 1st level without expending a spell slot. 

EX:

level 1: 1 of cr 1/4.

level 2: 1 of cr 1/2, 2 of cr 1/4.

level 3: 1 of cr 1, 2 of cr 1/2, 4 of cr 1/4