With the help from a mysterious creature, Elena turned herself into a magical girl to beat Zoid, a tentacle monster to save her sister, Emile.

How do I learn Japanese by watching anime?

Yes, you can learn Japanese with anime.
In fact, I believe it to be the most fun way to pick up hundreds of words, kanji, and grammar with the right methods and program.
In order to do that, however, there are a few things you must do to learn and retain this new information. Turn off the English subtitles. Be able to read hiragana and katakana confidently. Have a basic understanding of easy Japanese grammar. If you can manage to turn off the English subs or block them, you will already be learning more Japanese than 90% of anime fans out there.
It’s quite scary and difficult to do this at first, but it can certainly be done.
You will begin to train your Japanese ears and can even learn basic words just from context alone.
Start with shows that you have seen before or anime with very basic plots (i.e.
One Punch Man), Of course, just simply watching your favorite shows will not be enough.
You will need to go to kitsunekko.net to find the Japanese subtitles for the specific episode you wanna learn from.
It’s amazing how many series you can find the subtitles for.
You will need some basic hiragana and katakana reading skills and some grammar knowledge to be able to read though it quickly to find the lines you wish to learn. When you have located the line that you wish to learn, break down the sentence or sentences completely and learn all the new vocabulary, grammar points, and kanji within them.
This alone will not retain the information, so I recommend using Cloze flashcards in the free flashcard program Anki. In Cloze flashcards, contexts or sentences that you have learned before will be shown on the front side.
The exact sentence will be shown, yet a single word or grammar particle or kanji will be missing.
It is your job to recall what is missing based on the context and then write the answer in your notebook. Create flashcards for 40 minutes and review them for 20 minutes every day. Here is a video I did if you would like to see this all in action :)